The Audi bounced out of the industrial estate as Kate took the speed bump without slowing. Two hundred yards in front of her she could see her suspect hightailing it along the slip road leading to the M3.

She held the radio to her face. ‘This is Charlie-Victor-Two-Zero-Zero-Five in high-speed pursuit of suspect Niall Renshaw. He’s driving a 2012 red Porsche Boxster, registration is Kilo-Yankee-Six-Two-Mike-Romeo-Kilo. I am pursuing in a grey Audi TT, registration Hotel-November-One-Five-Hotel-Papa-Papa. I need backup to intercept him. Over.’

The Boxster joined the motorway and cut across two lanes, disappearing from view behind a supermarket lorry. Kate dumped the radio into her lap, dropped a gear, and shot down the hard shoulder of the slip road, cutting back onto the motorway and almost clipping a caravan crawling along the inside lane. The blue lights built into the grille at the front of the car were all the warning she could offer.

Her radio burst back into life. ‘Charlie-Victor-Two-Zero-Zero-Five received. I have two units joining you at junction 11, ma’am. Over.’

Kate lifted the radio, almost losing control of the wheel. ‘Received.’

The dashboard display flashed with the supe’s ID and she tapped her Bluetooth.

‘Matthews, what the hell is going on?’

‘He deserted the scene and I’m on his tail.’

‘Where?’

Kate pulled around a supermarket lorry, and could just make out the Boxster a quarter of a mile ahead. He had to be doing over a hundred to be pulling away from her that fast. She darted into the outside lane and floored the accelerator.

‘M3, sir. Joined at Eastleigh, heading East towards—’

‘Jesus! On whose authority?’

‘Sir, there wasn’t time to—’

‘Pull over now! There’s too much at stake here. I don’t want him panicked into doing something stupid. There’ll be other chances.’

‘But sir—’

‘I don’t want you causing an incident. End the pursuit.’

She flashed her lights at the Range Rover directly in front and gesticulated for him to move as she charged up behind him.

‘Sir, I wouldn’t do anything to risk—’

‘Desist, Matthews. That’s an order. You can’t keep pushing yourself like this.’

The Porsche was still eating up road, but she was finally gaining on him, her hands clammy against the leather strapping of the wheel. ‘Sir, I’ve got two support vehicles on the way. I need to keep him in sight until they can intercept.’

There was a pause. ‘Where will they join?’

‘At Winchester. I still have eyes on him.’

She was still gaining.

‘I want you to leave the pursuit when the patrol cars join. We need you back at the crime scene straight away, they need the SIO on-site.’

There was no point in arguing with him. ‘Understood, sir,’ she said through gritted teeth.

‘Do not engage with him, Matthews. I mean it. I want to hear you say it.’

They’d now passed the next junction, and the signs at the side of the road showed there was a mile until the Winchester turn-off.

‘Matthews? I want you to respond,’ he repeated, louder this time.

‘I’ll leave at Winchester, sir.’ She cut the call, and pushed the speedometer on. Now she was only four car lengths behind Renshaw.

Suddenly he jerked into the middle lane to the sound of blaring horns. Kate couldn’t copy the move as an SUV was blocking her path. She forged forwards, cutting in front of the SUV and then over again as she saw the Porsche dart up the slip road. He must have spotted the patrol cars on the road ahead.

‘Shit!’ she shouted, before jabbering into the radio. ‘This is Charlie-Victor-Two-Zero-Zero-Five, the suspect has left the motorway at junction 12. Are there any other cars in the area?’

‘Negative, Charlie-Victor-Two-Zero-Zero-Five.’

‘He’s heading north towards Winchester. I’m in pursuit, but I need backup. Over.’

‘Received. Over.’

She hadn’t lied; the supe had told her to exit at Winchester, to maintain eye contact until backup could intercept, which is exactly what she was doing.

The Porsche raced through a red light, narrowly avoiding a collision with a double-decker bus. The light went amber as Kate mounted the kerb, shot across the grass and back onto the road, only two car lengths behind him now.

‘I’ve got you, you son-of-a-bitch,’ she yelled at the windscreen.

She followed him onto the single carriageway and thumped the steering wheel in elation as she saw a tractor pull into view just beyond the bend in the road. With the stream of traffic coming the opposite way, there was no way he was overtaking.

But she was wrong. Suddenly, he shot out and accelerated into an opening. It was an insane move, but if she didn’t replicate it, she’d lose him. She pulled the wheel right and tucked in behind him, praying that he would hurry so they could both get past the tractor before the bend that was hurtling towards them.

As the nose of her Audi crept past the tractor, Renshaw slowed, trapping her in. She pressed harder on the accelerator, nudging his bumper. She saw him glance up into the rear-view mirror and give her a sickening grin. She bumped him again, but he remained where he was. What was he playing at?

He swung left.

The breath caught in Kate’s throat as sunlight reflected off the windscreen of the 4x4 approaching. A second later, she was flying through the air.