An arsonist who set fire to his pregnant girlfriend's home when she and her family were inside has been jailed for four years.

Mark Griffiths and Emma Howe were celebrating their engagement just hours before he started the blaze but the couple had an argument in a pub.

Griffiths, 24, of Stillingfleet Road, Hartcliffe, shoved burning material through the letter box at his girlfriend's home, in Camberley Road, Knowle, while she was inside with her mother and sister.

The family escaped and Griffiths was arrested two days later.

He admitted a charge of arson being reckless as to whether life was endangered, together with offences of criminal damage, theft, and threatening to damage property, taking a vehicle without consent and common assault.

A judge at Bristol Crown Court jailed him for four years and told him a previously suspended prison sentence of 35 weeks – for harassment and assault occasioning actual bodily harm – would be activated too.

Griffiths and Ms Howe had been in a relationship for 18 months by the time of the attack, on September 18 last year. She was pregnant with his child and they had just got engaged to be married.

The went out to celebrate but they argued and separated soon into the evening.

Griffiths and Ms Howe were seen arguing in the Tap and Barrel pub in Bedminster, where staff had to forcibly remove Griffiths after it was said he had been threatening to Miss Howe.

Staff had to pin him against a wall to stop him from getting into a car with his girlfriend when her mother arrived to pick her up and take her home.

Griffiths was seen outside the home at 9pm, when he swore at Ms Howe and smashed a glass panel in the door with a bottle before running off.

Later in the evening he returned and neighbours heard him shouting at Emma.

He was threatening to torch the premises and burn the house down.

Griffiths made off, only to return some time after midnight to carry out his threat.

Stephen Dent, prosecuting, said he pushed lighted material through the letter box, which started a significant fire that caused £2,563 worth of damage.

Mr Dent said a forensic scientist found the fire posed a clear danger to the lives of the occupants because of its proximity to the stairwell.

Griffiths also stole a moped from a pizza delivery driver in Knowle on July 25 last year and assaulted his victim by hitting him on his crash helmet.

He was arrested for the offences while he was in custody for the arson attack.

Nicholas Fridd, defending, said Griffiths knew Ms Howe and her family were awake when he set fire to the house.

He said Griffiths often drank too much despite having had a liver transplant.

Jailing Griffiths for four years and 35 weeks on Friday, Judge Julian Lambert said: "You know the wickedness you have done.

"Arson on a dwelling late at night is wicked.

"You know that I regard your offending as so serious, fines and community sentences can't be justified."