David Cameron has sent a personal message to the parents of a young girl killed in a car accident as their Zimbabwean relatives strive to have visas granted to attend her funeral in Britain.

In his letter, the Prime Minister told Charity and Wellington Gada, the parents of five-year-old Andrea, that he knew "the struggle of losing a child first-hand".

Andrea died after being hit by a car in Eastbourne on December 17, but her funeral has been postponed due to uncertainty over whether her relatives will gain permission to travel to the UK.

Mr Cameron told the Gadas that he has asked Home Secretary Theresa May to look in to the issue surrounding their relatives' temporary visa applications after they were rejected twice.

In his letter to the parents, Mr Cameron said: "I was very sorry to learn of the tragic loss of your daughter, Andrea, in a road traffic accident.

"I know the struggle of losing a child first-hand and hope that, in time, you find strength in the memory of the happier times you shared with Andrea.

"I have asked the Home Secretary to look in to the issue of your family members' applications for visas and provide a full response to your letter.

"You and your family are in my and Samantha's thoughts and prayers and I wish you all well for the future."

Andrea's maternal grandparents, retired street trader Stanley Bwanya, 65, and Grace, 57, and aunt, Monalisa Faith, 21, were last month denied access to the UK by the Home Office, Mrs Gada said.

The decision was then later upheld amid concerns that they might abscond. It prompted an e-petition signed by more than 120,000 people calling for the visas to be granted.

Eastbourne's Liberal Democrat MP Stephen Lloyd has said he would act as a guarantor to ensure that the relatives returned to Zimbabwe after the funeral.

Mrs Gada, 32, said the intervention of Mr Cameron has given the family fresh hope that the visas will eventually be granted, but they remained cautious.

She said: "We are just waiting now and hoping that we will get a good outcome, as we have been through this before.

"Everything is on hold and in suspense. We just want to find out the final decision. The Home Office has just been assuming that because of the situation in Zimbabwe, our relatives will not go back.

"But if they had any of these intentions, why would we have gone so public?"

Mr Gada, 38, said: "Everything is guided by the decision of the Home Office."

Mrs Gada has said her relatives pose no risk to the UK and simply want to travel over to support them and grieve for Andrea.

The community of Eastbourne has helped raise money for the relatives to attend, and the family have offered to wear electronic tags and report to the local police station.

In the online petition, Mrs Gada pleaded for her relatives to be allowed in to the UK.

She said: "Losing a child is one of the hardest things a person can experience, and at this time myself and my husband are both longing for the support of our family.

"Having our family together at this time is incredibly important to us, and an important part of our culture.

"Andrea was a wonderful little girl and she deserves a proper farewell. At the heart of it, all I really want is to have my mother at my side whilst I grieve the loss of my child."

A Home Office spokesman said: "All applications are considered on their individual merits, including any compelling and compassionate circumstances, and in line with the immigration rules."