Extra police phone lines, set up to field calls during the Ross Doyle inquiry, are to be kept open until Monday in the hope that vital witnesses will come forward.

A reward of £10,000 is on offer to anyone who helps convict the car thieves who knocked down nine-year-old Ross on December 13 last year in Blackbird Leys, Oxford, and left him dying in the street.

Officers had planned to close the confidential lines, which are manned by detectives, at 7am on Tuesday but have extended them for a further six days.

Police say they have received a positive response to their investigation but they are still seeking hard evidence that will lead to the joyriders who killed Ross being charged.

It is hoped the extra time will give people with information more time to check their consciences and call in.

Det Insp Dermot Norridge, of Oxford police, said: "We still need people to come forward with information to allow us to complete this inquiry.

"We have had a positive response from members of the community and officers are currently acting on the information received.

Det Insp Norridge has again asked members of the Blackbird Leys community to think where they were on the night Ross was killed, as he walked home from football training.

He particularly wants to hear from people who were on Pegasus Road, where the accident happened, between 8.30pm and 9pm and anyone who saw the stolen red Vauxhall Astra, registration F581 HUR, which hit Ross.

The information lines are 01865 266276 or 01865 266257. Crimestoppers can also be called on 0800 555111.