A lodger stabbed a mother-of-three and her partner to death when a row broke out about the temperature of the shower, a court has heard.

Mechanic Foster Christian, 54, allegedly launched a frenzied attack on Natasha Sadler-Ellis and Simon Gorecki at the home they shared in Canterbury, Kent.

The row is said to have broken out when Christian turned on a kitchen tap while Mr Gorecki was showering, triggering a sharp change in temperature.

When Mr Gorecki told him to turn it off, Christian allegedly told him: 'F*** off you mug'.

About 40 minutes later, Christian is alleged to have launched his stabbing spree, knifing Mr Gorecki five times - including four times in the back - as well as 40-year-old Ms Sadler-Ellis.

Foster Christian (left), 54, is on trial accused of the double murder of a mother-of-three and her partner in Canterbury, Kent

Christian is also accused of stabbing Ms Sadler-Ellis's 20-year-old son Connaugh Harris, who later tried to save his mother as she lay dying on the floor.

The defendant is also accused of seriously injuring a 16-year-old boy, who cannot be named for legal reasons. He denies two counts of murder and two charges of wounding with intent.

Today, during the opening of the trial at Maidstone Crown Court, the court was told how the trio were at the property at around 7pm in March this year.

Prosecutor Philip Bennetts QC said that, when Mr Gorecki - a former fishmonger- complained about the tap being turned on, Christian retaliated angrily.

He said: 'He used a tap which caused the temperature of the water in the shower to change. Simon shouted at Mr Christian who told him to "F*** off you mug".'

The pair then began arguing with one another. The court was told how Mr Harris was on the phone to his mother at the time and rushed to the address, along with the teenage boy, to 'diffuse the situation'.

When he arrived, Mr Harris found Christian, Mr Gorecki and Ms Sadler-Ellis having a row upstairs.

The jury heard how Mr Harris tried to calm the situation but that Christian and Ms Sadler-Ellis soon began shoving one another.

When Mr Harris tried to intervene, Christian struck him, the court was told.

The teenage boy then retaliated by punching Christian, but the alleged killer brought out a knife wrapped in a plastic bag, the court heard. Christian then allegedly began his attack, stabbing his two alleged victims to death.

Mr Bennetts said: 'They didn't know that Foster Christian was in fact using a knife at that stage.

'The knife was held in a bag and you may at some stage when you consider the evidence wonder about that and why there was a bag about the knife.'

Natasha Sadler, 40 (left), and her partner Simon Gorecki, 47, (right) were found stabbed to death

Ms Sadler-Ellis, who was 5ft 6in, suffered four stab wounds to her body.

As well as the fatal wound to her heart, she was stabbed just above her left eyebrow, with the knife plunging down internally to her lower jaw, the court was told.

Mr Gorecki, 48, died as a result of one of his stab wounds penetrating his right lung, the court was told.

The jury heard how, after the alleged attacks, Christian called police and said the knife was his.

But he then changed his account to 'their knife', claiming he had grabbed it from them and they had taken it back.

Asked by the operator if he was okay, Christian calmly replied: 'No, I'm not, thanks.

'They hit me with a beer can. I don't know what else with. They were hitting me with beer cans and bottles so I just grabbed a knife from my rack.

'They were still doing it, just beating me and beating me and beating me. And they are still here.'

The court heard how police arrived at the house at around 7.40pm to find the teenager lying at the top of the driveway, Ms Sadler-Ellis on the kitchen threshold and Mr Gorecki on the kitchen floor.

Christian is also accused of stabbing Ms Sadler Ellis's 20-year-old son Connaugh Harris (left and right) - a serving soldier - who was left in a critical condition in hospital following the alleged attack

Mr Harris had been giving the teenager first aid on the driveway after trying to help his mother and carrying out CPR on Mr Gorecki.

The court heard how the teenager asked Mr Harris if he would die as he put him in the recovery position.

He said he initially thought he had been punched in the stomach during the violence but then saw his 'guts were hanging out'.

In an interview played to the court, the youngster told police: 'I looked at Connaugh and said "I have been stabbed".

'He said "It's alright mate". I was like "oh God" and I just remember this huge pain and I was like "Am I going to die?" and he said "No mate, no" and he lay me down on the wall just outside the house.'

The teenager also told the court that during the heated row Ms Sadler-Ellis accused Christian of 'creeping' on her at her home.

The boy said she told Christian she was 'sick of him coming past her house staring through her window'.

He also said Mr Gorecki told Christian: 'I'm going to run through you' but that it was not a threat to stab him.

As the 16-year-old boy was cross-examined over a TV link, he broke down in tears as he told the court: 'Unless you have been in that situation... I was doing what I thought was right.'

He said the whole incident happened in about 10 seconds and although he never saw a knife, Christian made 'stabbing motions'.

In an exchange with Christian's defence counsel, Rajiv Menon QC, the teenager strongly denied the barrister's suggestion that 'all hell broke loose' and they attacked Christian, with Mr Gorecki 'rushing forward' armed with a knife and shouting 'You black b*****d'.

Having laughed in apparent disbelief at the defence suggestions that the group were armed and had attacked Christian 'four against one', Mr Menon asked if the boy thought it was funny.

He replied: 'I find it funny how you can defend this. But I told you I punched him once, a 16-year-old, punching him because I was defending Natasha.'

Told by Mr Menon that the violence resulted from them not leaving the house and going back upstairs, the teenage boy said: 'It happened because he was shouting abuse and bullying everyone. Of course we could have not gone upstairs and not confronted him but that's happened.'

The teenager was left with a wound to his right forearm, a superficial injury to his right thigh, a cut to his abdomen, a 3cm whole in his large bowel and a large bleed to the iliac vein, which returns blood from the leg to the heart.

After surgery at the William Harvey Hospital in Ashford, he was transferred to intensive care.

The court was told how a police officer saw Christian, who was bleeding from a cut above his right eye and speaking on his phone and she shouted at him to go back upstairs.

The alleged murderer sat on the stairs and said he did not have a knife when asked by another officer.

He said: 'They attacked me with a knife. I got it off them and fought back. They were hitting me and attacking me. They took the knife back.'

The court was told how Ms Sadler-Ellis's blood had stained the upstairs floor around the threshold of Christian's bedroom, believed to be from the wound on her left eyebrow which poured out as she stood at the top of the stairs.

Mr Bennetts said: 'One explanation for the blood distribution around the top of the stairs is that she stood or knelt on one of the upper steps facing up the stairs while blood pumped from the wound on her left eyebrow.'

The jury was told that no alcohol had been found in Christian's blood but both the alleged victims had been drinking.

Naomi Toro, 36, had arrived at the house and was seen by a police officer leaving with the knife used to inflict the injuries.

When arrested on March 30 she took officers to where she had thrown the weapon into the River Stour from a bridge.

Mr Bennetts added: 'There is no dispute that Foster Christian killed Simon Gorecki and Natasha Sadler-Ellis.

'The defence served on the prosecution and the court a defence statement.

'In short it is asserted that Foster Christian was acting in reasonable lawful self-defence. The prosecution case is what he did was not reasonable.

'At the very least stabbing with a knife demonstrates as intention to cause really serious bodily harm.'