Dave and Finn's story that moved the judges and audience to tears

Finn the police dog is relaxing in the garden with his ‘dad’, Dave. Finn is at Dave’s feet, chewing on a yellow ball. Dave’s enjoying a cup of tea.

When we meet, they still haven’t figured out what they’ll be doing in tonight’s final of ITV’s Britain’s Got Talent, because they didn’t expect to get through, but neither, at the moment, seems all that bothered.

They are, indeed, the very picture of contentment.

Perhaps Finn, who Dave is convinced is psychic, has had a vision that it will all work out on the night – so why worry?

Or maybe, given their history, they simply have a healthy sense of perspective.

On October 5 2016, both nearly died in the line of duty. They were attempting to arrest a robber in a field in the early hours when Finn was stabbed in the chest with a ten-inch hunting knife by the suspect.

Hero police dog Finn, who survived horrific knife injuries while defending his handler from attack, sparked the successful Finn's Law campaign

As he lay on the ground bleeding dangerously, he found the strength to raise his body to shield Dave when the attacker made a second lunge towards his neck.

Finn took the brunt of the the blade in his head - and saved Dave’s life.

His story has melted the hearts of millions.

Finn’s talents don’t stop at selfless heroism. In Monday’s semi-final, Finn’s demonstration of his remarkable powers of ‘thought transference’ on the judges won him the public vote and a place in the final.

Finn is special, but Dave also has five other dogs. He is currently handler to two other police dogs

Finn the German shepherd, has been presented with the PDSA Gold Medal - the animals' George Cross

‘The whole act really comes from our incredibly close bond and I hope that comes across on stage,’ explains 42-year-old Dave, aka Police Constable Dave Wardell of Hertfordshire Constabulary.

‘When you spend so much time with an animal you very rarely have to communicate with words. You bounce off each other’s body language and I’ve very rarely had to give him a command when he comes out of the van, I guess he knows what to do from what I’m doing and saying.’

The ten-year-old German Shepherd is as calm and assured on stage as he used to be out on patrol before his retirement in 2017. Stage fright just isn’t an issue.

‘Finn couldn’t care less,’ says Dave. ‘You can imagine the situations that he has faced throughout his career. Police dogs have to be really bold and confident and it takes something quite special to become one – not all police trainees make it.

Once Finn was active, of 32 police dogs on our force he topped the league table for arrests in three out of seven years

‘On stage the other night, he was just like, yeah OK, what is it you want me to do, Dad?

‘I hadn’t thought of getting to the final. I’m not a performer. My world is not normally on a stage in front of 4,000 people and millions at home. My world is chasing through back gardens at 3am looking for burglars and car thieves so it has been something right outside my comfort zone.

‘But it’s been fantastic. Finn helps calm me on stage. When you’ve got your best friend there and you can give them a bit of a ruffle when you’re nervous, it helps you to relax.’

The police dog was left with near-fatal injuries after he was stabbed repeatedly by the 16-year-old thug, who also wounded his handler PC Dave Wardell

I gaze into Finn’s big soulful brown eyes. What message does he have for me?

I’m not getting anything.I look harder at Finn.

Wait, something’s coming through.

It’s an instruction: ‘Throw the ball for me!’ Now he is telepathically transmitting a second message.

Finn tackled the armed robbery suspect as he tried to escape over a fence in Stevenage, Hertfordshire, in October 2016.

Here it comes: ‘Fetch me a treat!’ Or maybe that’s just me wanting to spoil this delightful, gentle, chap chilling on the grass.

Finn and Dave are inseparable. At the family home in Hertfordshire, where Dave lives with his wife, Gemma, who is also a PC, and their three daughters, Jaymee, 12, Tia, nine and India, seven, Finn sleeps with Dave and his wife, Gemma, in the marital bed and the first thing they do every morning is have a cuddle.

‘He knows me better than anyone else and I know him better than anyone else. He gets whatever he wants. If he wants the end of the bed, he’s got it, if he wants the sofa, he’s got it. If it wasn’t for Finn, I wouldn’t be here.

PC Wardell recalled: 'In a split second, I saw the man lunge at Finn's side with a weapon. 'As he pulled away, I saw a 10in blade, covered in Finn's blood'

‘Our wife, I mean, my wife, I think is probably a little bit jealous of the relationship we have. He’s literally my shadow.’

Finn and Dave go everywhere together. On a recent holiday to Florida, the thought of putting Finn in kennels was naturally unthinkable, but so too was the thought of putting Finn in the hold of an aeroplane for ten hours.

What Dave wanted was Finn next to him, sitting on the aircraft and that’s what he got, persuading an airline to give Finn a seat - in Premium Economy, for extra legroom - in recognition of his special status.

'The man then lunged at me with the blade but Finn, despite being seriously hurt, grabbed hold and stopped him from landing a fatal blow,' the officer said

Finn is special, but Dave also has five other dogs. He is currently handler to two other police dogs, Hero Diesel, a female German Shepherd, and Pearl, a Springer Spaniel drugs sniffer dog.

The family also have three pet dogs, Maxi, a four-year-old German Shepherd bitch who is a rescue dog, Harper, a French bulldog bitch, and Roary, an English Mastiff.

The family also have a parrot called Roxy and a cat, Kitty - it’s quite a menagerie.

Despite suffering two serious stab wounds and a punctured lung, Finn kept hold of the suspect, allowing PC Wardell to wrestle him to the ground

Dave managed pubs and restaurant before joining Hertfordshire police 16 years ago, aged 26. Finn was his first police dog and they bonded instantly. The pair had lots of adventures, but until the night of October 5 2016, had always emerged unscathed.

It was shortly before 2am when Dave and Finn took a call saying there was a ‘suspicious incident’ at a property. When they arrived, there were already two police units on the scene.

‘I unclipped Finn and he ran after the suspect and caught up with him quite quickly. He grabbed his leg and pulled him down. It was just like hundreds of jobs we’d ever been too. It was all going well, we’d found our baddie.

‘Finn had him on the ground, with his leg in his mouth, but suddenly he thrust forward towards Finn’s chest. The first I realised it was a knife was as it was coming out of Finn’s chest. My world stopped.

He was back on duty within three months, although he is now retired and has appeared on Britain's Got Talent

‘Luckily for me, dogs are masters of body language, of reading people, because as he went towards me, aiming at my face and neck, Finn saw it.

‘He lifted himself up and put himself in the way. The top of his head was sliced open. I was stabbed in the hand, but not seriously.

‘Even then, as he lay there bleeding, he would not let go of the attacker’s leg. And he’d saved my life.’

At this point Dave took hold of the man and slammed him down on the ground twice and he let go of the knife just as his police colleagues arrived. They took hold of the suspect - and only then did Finn let go of his leg - and only when Dave told him to.

‘I laid Finn on the grass, there was lots of blood. I shouted, “I need a vet”. A colleague ran over and said he’d drive me.

‘I put Finn in his cage in the back, he was in a lot of pain. The van was covered in his blood.

‘When we got to the vet’s, Finn found where I’d been stabbed in the hand. He was lying there, effectively dying, struggling to breathe, and yet he started to tend to my stab wound. He was still looking out for me.

‘That broke my heart.’

Finn had been stabbed in one of his lungs. The knife had missed his heart by a centimetre. His oxygen levels were plummeting as his lungs struggled to inflate.

Finn had been stabbed in one of his lungs. The knife had missed his heart by a centimetre

Dave was told Finn had to get to another veterinary hospital which had more specialised equipment.

There, the veterinary surgeon asked David if he wanted to go in to the operating theatre and say goodbye. ‘I went in there and burst into tears and told him I loved him.’

Dave pauses; he’s crying. He instinctively reaches down to put his hand on Finn. He held a vigil outside during Finn’s four hours in surgery.

‘I remember the surgeon, Rob Adams, who’s now a family friend, coming out, saying he was happy with surgery, but the next 48 hours were really important.

‘I was allowed to see him for five minutes. He was under so much anaesthetic, and again he saw me and gave me a single tail wag but the biggest you could ever imagine.

‘But he just looked so broken.’

Back home, Dave couldn’t eat or sleep and was overwhelmed with relief when he took the call the next morning that Finn had made it through the night.

Finn worked for another four months before being retired, as Dave had always planned, on his eight birthday in April 2017

‘They said, he’s starting to be a bit cheeky, he’ll only eat freshly cooked chicken.

‘I saw him later that day. It was very emotional. They gave us a consulting room and Finn and I fell asleep, lying next to each other, right there and then.’

A few days later, Finn was allowed to return home. Dave set up a camp bed in the living room and stayed there for four weeks, slowly nursing Finn back to health.

‘The first couple of weeks he was really withdrawn, he wanted to be with me the whole time and I liken it, if you want to humanise it, he was disappointed with the world, he couldn’t understand how this had happened.

‘But then he started to be more like himself. Two weeks after the attack, he picked up a tennis ball and threw it at me.’

Finn returned to duty on 22 December 2016.

‘If Finn had said to me at any point, you know what, I don’t want to do this, if he had shied away from any exercise, I would have retired him. He wanted to go back to work. The vet said he thought his recovery was nothing short of miraculous and he puts it down to he had a job to do so therefore he had to get better to go back to do his job.

On their first outing, they caught a car thief.

‘He dragged me through the streets into a field. We found the thief in the stable block. As I made the arrest, I burst into tears. “The thief said, are you all right?” Looking back, it was quite funny. It’s just Finn and I had been through such a journey together.’

Animal Welfare (Service Animals) Bill was introduced in 2017 and went through Parliament last year. In April this year, it was passed by the House of Lords and days later, given Royal Assent

Finn worked for another four months before being retired, as Dave had always planned, on his eight birthday in April 2017.

Finn’s retirement was most richly deserved – but brought its own problems.

‘When Finn retired he found it very hard for me go to work without him and he would sit in our bay window watching for me until I got home,’ says Dave.

We both struggled. He’d saved my life. To leave the house without the person (Dave habitually refers to Finn as a person) who’d saved your life was very hard.’

Dave was later shocked and upset when the offender who nearly killed Finn walked away from court with only a minimum penalty because no law was in place to protect police animals from harm.

And the injury to Finn was classed simply as criminal damage.

His dad vowed to win justice for Finn and began his campaign to introduce the Finn’s Law.

The Animal Welfare (Service Animals) Bill was introduced in 2017 and went through Parliament last year. In April this year, it was passed by the House of Lords and days later, given Royal Assent.

The Act will come into force on 8 June, and will mean that causing unnecessary suffering to a service animal will be an offence in England and Wales.

‘This was important for Finn, but it’s not only Finn who has an incredible story,’ says Dave. ‘Police dogs do get injured, they do get attacked.’

Today Finn and Dave value every minute they have together. Finn isn’t getting any younger, and Dave dreads a future without him. ‘If I start to talk about that I might burst into tears.’

But he says he has hopes that one day there will be a ‘Son of Finn’.

‘I’ve always dreamed of it, especially after that night. Gemma and I are thinking about it. Maxi, our pet German Shepherd, will be the mother of Son of Finn.’

The Act will come into force on 8 June, and will mean that causing unnecessary suffering to a service animal will be an offence in England and Wales

A friend suggested Dave enter BGT to raise awareness about Finn’s Law and animal welfare.

In the semi-final, the four judges, Simon Cowell, Amanda Holden, Alesha Dixon and David Walliams, were asked to look at Finn and pick a name, a number, a word and a specific time, which was being transmitted to them ‘telepathically’ by Finn. (Of course, there are suspicions it’s a trick, playing on the unique bond between dog and master, but who cares?)

A video was then shown of Finn’s day – which showed Finn to have succeeded in his thought transference. The time, eight o’clock, for example, had popped into David Walliams’s head - and Finn’s alarm clock revealed he got up at eight o’clock.’

Finn’s act – and his story – went down a storm and the public voted him the winner out of the eight acts.

Now Finn and Dave are preparing, in their uniquely laid-back way, for the tomorrow’s final.

‘We’re not sure exactly what we’re doing yet, but we have lots of plans. There’s been talk of horses and helicopters, but we’ll have to see.’

Some of Finn’s millions of fans think, who cares about magic tricks?

Finn is a hero who was prepared to lay down his life to save his dad’s life – and that, alone, they say, is more than enough to win BGT.

- Natalie Clarke for The Daily Mail