Keir Starmer’s sister-in-law has told of her terror after arsonists firebombed the Prime Minister’s home where she was living with her family.

Judith Alexander was lying in bed when she heard loud bangs as Roman Lavrynovych, 21, allegedly set fire to the front door of the property in North London, which she had been renting from Sir Keir since he moved to Downing Street.

The 21-year-old Ukrainian-born construction worker and part-time model is accused of carrying out three arson attacks targeting the Prime Minister on the orders of a mystery Russia figure who offered him £1,500.

In a statement to police, Ms Alexander recalled how she struggled to breathe as the fire took hold on May 12 last year.

She had been responding to a text message on her phone at 12.50am when she heard an explosion.

‘All of a sudden, I heard two bangs. It was very loud and sounded like two wheely bins had been thrown at the door,’ she told police.

‘I did not see anyone on the street but when I looked down I saw smoke and an orange glow where the front door was.

‘The smoke was like soot coloured. I would describe it as black billowing smoke and orange fire.’

Ms Alexander said she was ‘scared’ as she called 999 and her partner went downstairs to investigate.

Her nine-year-old daughter’s bedroom was located directly below the front door.

In a statement read to jurors at the Old Bailey, Ms Alexander said: ‘We could see the smoke was getting thicker and going upstairs.

‘I was frantically trying to call my sister Vic and anyone that would pick up my call but I could not get hold of anyone.’

The family donned Covid masks to protect themselves from the billowing smoke, she said.

Referring to her daughter as ‘B’ she added: ‘I was calming B, my daughter, down.

‘During this time B was really frightened. B was extremely worried about her dad as he was downstairs.

‘I was locked in the room upstairs with B. The house was full of smoke. I have asthma and was struggling to breath.’

Firefighters arrived within ten minutes to extinguish the flames.

Afterwards, Ms Alexander could not sleep as she lay thinking how close her daughter’s room had been to the fire worrying ‘if I did not wake up what might have happened’.

Lavrynovych is now on trial with Petro Pochynok, 35, and Stanislav Carpiuc, 27, who are accused of torching that property, a car which once belonged to the Prime Minister and a house in Islington managed by a company which Sir Keir had once been a director of.

Within hours of the blaze, police tracked down Lavrynovych to his home in Sydenham, south-east London and arrested him in bed on May 13.

Jurors heard that police found trainers with a trace of turpentine substitute, a petrol can and a bottle of white spirit which bore the defendant’s DNA.

In police interviews, he denied being involved in the fires, but later claimed someone had asked him to carry out the attacks.

Lavrynovych told officers: ‘I think you need to speak to a different person.’

When asked who, he answered: ‘I don’t know, I never saw this person.’

In a prepared statement, he said a contact known as El Money had offered him £1,500 to carry out surveillance at two addresses, but he claimed he never paid.

Lavrynovych added: ‘He threatened me by saying that I would have to do the job as he knew where I lived.’

The three defendants from London deny conspiracy to damage property by fire between April 1 and May 13 last year.

Lavrynovych also denies damaging two properties by fire with intent to endanger life or being reckless as to whether life was endangered on May 11 and 12 last year.

The trial continues.