The British government is to face a legal challenge over its failure to launch a public inquiry into security force collusion in the murder of Belfast solicitor Pat Finucane.

Relatives of Mr Finucane are to seek a judicial review of British Prime Minister David Cameron's decision that barrister Desmond de Silva should instead review the papers on the case.

Mr Finucane's widow Geraldine left a meeting in Downing Street in October when she was informed of the British government's plan.

She has now confirmed her intention to launch a challenge in the High Court in Belfast next week.

Northern Secretary Owen Paterson apologised in Westminster for the state's collusion in the 1989 killing in which Mr Finucane was shot by gunmen from the UDA in front of his wife and children.

The Finucane family said that having considered their options, they were now to mount a legal challenge.

Ms Finucane said: "Not for the first time have we had to resort to legal proceedings to vindicate our legal rights.

"The Cameron decision is also incompatible with Article 2 of the European Convention on Human Rights (the right to life).

"We take the view that the decision not to hold a public judicial inquiry is just another obstacle which we will have to overcome.

"We are determined to get to the truth surrounding my husband's murder. Our campaign will continue."

The legal papers will be lodged in the High Court within days and a date for hearing will be sought.