The trial of four people arrested following a house fire that killed a Brooklands couple began at Manchester Crown Court on Thursday.

Maureen and Alex Cochrane died after a fire at their family home, on Warmley Road, on January 12 while their teenage daughter suffered serious injuries.

A teenage girl helped murder a couple in an arson attack after waging a hate campaign against their daughter, a court heard today (Thursday).

Natalie Connor, 18, was said to have "obsessive enmity" for schoolgirl Lucy Cochrane, 16, and her parents because of a playground fallout.

Her obsession eventually turned to murder when Natalie and mother Jane, 39, incited her father Michael Connor, also, 39, to start a fire at the Cochrane's family home in Baguley, near Wythenshawe, Greater Manchester, a jury heard.

Michael, 39, went on a drinking session with his wife and daughter before pouring petrol late at night through the letter box of the two up two down terraced as the Cochranes were upstairs.

The blaze was so fierce it, the temperature in the hallway reached 1,000 degrees centigrade in just over two minutes.

Lucy's mother Maureen Cochrane, 45, a shop assistant, made a desperate 999 call but died in the fire.

The teenager's father Alex, a 54-year-old baggage handler from Manchester Airport, got out of the house but died in hospital three days later.

Lucy was found under her bed and was carried out unconscious from the house but despite serious injuries, managed to survive the blaze.

Manchester Crown Court heard Mrs Cochrane had called police over earlier attack on her home just five days before the murders but officers took no action.

"It is a tragedy of epic proportions," said Mr Alistair Webster QC,prosecuting.

"A vulnerable young girl lost her parents and suffered serious injury herself. It arose from and was motivated by such a trivial and nonsensical cause.

"But the evidence is clear - members of the Connor family through the incitement of Natalie and her mother hated the Cochrane family who paid for this obsession with their lives."

The midnight murder on January 12 this year was the culmination of a "campaign of harassment" of Lucy and her family - in particular from Natalie and her mother.

Mr Webster said Natalie and Lucy and been at Newall Green School in Wythenshawe over a number of years before both transferred to the same college.

"Lucy has learning difficulties but was regarded by all the staff who dealt with her as a pleasant if occasionally vulnerable girl," said the QC.

"Natalie at some stage seems to have fallen out with Lucy and from that point there appears to have been a campaign of escalating unpleasantness aimed at Lucy and her family."

"It started out with insults and progressed to various false allegations made by Natalie who was fully supported by her mother.

"It was an almost obsessive pursuit of some imagined slight and a refusal to let the matter lie and it is that obsession which lies at the heart of this tragedy."

The court heard Lucy was arrested on "an entirely false" allegation of assault made by Natalie and there were a number of incidents of vandalism on the Cochranes' car.

Teachers were alerted to the feud and the college made special provisions to make sure Natalie and Lucy's paths did not cross. Lucy's mother Maureen was said to have suffered as a result of the strain and lost a great deal of weight.

Towards the end of 2005 matters seemed to ease off between the two girls but it blew up again in January 2006 when Lucy and Natalie were involved in an incident on board a bus.

On January 7, Mrs Cochrane was woken up by the family dog to find a inflammable-looking liquid on her front door. An attempt had also been made to uproot a tree in the Cochranes' garden.

Mrs Cochrane called police but no officer came to take a sample of the liquid on the door. "Maureen was very upset by what she had discovered - upset and frightened," added Mr Webster.

"But the police took the view that as nobody had witnessed what had gone on,there was little that could be done whatever the suspicions might be."

The court heard officers promised to look into installing a CCTV camera but in the end a neighbour lent the Cochranes a dummy one.

On the day of the murder itself Michael Connor had twice gone to son's school, drunk and complaining the lad had been bullied.

He told teachers: "If the school doesn't get this bullying sorted out then I will sort out the kids and the parents."

He left to go the nearby Wendover pub to meet his ex-wife and daughter and was spotted in deep conversation with his mother-in-law about the resentment of the Cochranes.

Michael returned to the school later in the afternoon saying: "I'll sort out the pupils, sort out the parents then come back to sort out the teachers."

At 5pm the Connors - who did not own a car - went to Tescos store where they bought a silver petrol can before Michael bought three litres of petrol from a nearby garage.

"Given the hatred which the women clearly felt for the Cochranes and given the use to which the petrol was put it is quite clear they had incited Michael Connor into a plan to set the victims' house on fire," said Mr Webster.

At 10pm the three Connors were in the nearby Gardners pub where the women appeared to have been crying and Michael told a regular: "I have business to see to - it's got to be done tonight."

Two hours later a neighbour spotted a drunken man near the Cochrane's house and heard shouting and laughter before hearing a thud as the fire took hold.

Michael Connor was later spotted walking past the house up to four times "surveying his handiwork." Mrs Cochrane called police but by the time the call ended the fire had entered her bedroom.

In a 999 phone call to the fire brigade she said: "Can you hurry up - I've become overcome by fumes. Please just come."

Mr Webster added: "Mr and Mrs Cochrane never had a chance of getting out of their door.

"Within 18 seconds the fire would have filled the staircase and within two a quarter minutes the temperature in the hallway would have been in excess of 1,000 degrees C.

"The ignition of petrol by a wooden door with a mat or carpet inside the door and with clothes nearby in a two up two down terrace rapidly makes escape impossible and death or serious injury inevitable."

Mr and Mrs Cochrane and their family dog were trapped in their bedroom whilst Lucy was in her bedroom at the rear of the house.

The Connors were later arrested but the two women denied involvement in the blaze.

Natalie claimed she had not see Lucy for a year whilst Jane said there was no trouble between her daughter and Lucy and claimed that any problems had been sorted.

But when Michael was charged he said: I regret what I've done. I never mean it to harm anybody or kill anybody. I just meant the scare them so they would leave my family alone."

Michael Connor, of Hall Street, Offerton, Stockport, his ex-wife and daughter, both of Wellfield Road, Wythenshawe, all deny murder and attempted murder.