Hostages shot by Islamic captors as SBS attempted rescue mission

Cameron authorised operation to free Briton and Italian as 'window of opportunity arose'

Two hostages, a Briton and an Italian, held by Islamist militants in Nigeria have been killed in a firefight while UK Special Forces were trying to rescue them. Members of the Special Boat Service and Royal Marines were alongside Nigerian troops in the operation at the city of Sokoto when Chris McManus from north-west England and Franco Lamolinara lost their lives.

David Cameron said the two men were "murdered by their captors" and insisted that he had authorised the mission early yesterday morning because "a window of opportunity arose to secure their release. We also had reason to believe that their lives were under imminent and growing danger".

The Independent understands that intercepted telephone calls had revealed that the group which had seized 28-year-old Mr McManus and Mr Lamolinara were planning to "sell" them to a more hardline faction who may well have murdered them.

British and Nigerian negotiators had been talking intermittently with the kidnappers who called themselves "al-Qa'ida in the Land Beyond the Sahel" to obtain the release of the two men. However, "third parties" began to get involved in the talks, raising fears that the group may not be in control of their victims for much longer.

"Al-Qa'ida in the Land Beyond the Sahel" is believed to be part of the Boko Haram group which had carried out a string of recent attacks in Nigeria in which dozens of people were killed. Officials say that the demands they had made for the release of the Briton and the Italian, which included release of prisoners, were "confused".

The SBS team, which was about a dozen-strong, and a more than 30 Royal Marines are believed to have been flown into Nigeria in the past few days. The two hostages are said to have been shot dead by the kidnappers during the early part of the operation, when two of the kidnappers were also killed.

The Italian government said it had only been informed about the rescue attempt after it had begun. A spokesman added that Mr Cameron had called Italian Prime Minister Mario Monti to inform him of the "tragic conclusion" of the operation.

British diplomatic sources maintained, however, that the Italians, who had no presence on the ground, had been told and had agreed that a move may have had to be made at short notice and that any protestations were "disingenuous".

The gun battle at the house where the hostages were held was said by an Associated Press reporter who reached the scene to have lasted for much of yesterday afternoon and into the evening. Security forces surrounded the property and cordoned it off for half a mile in every direction, but an ambulance was seen ferrying away a number of wounded people.

Nigeria's President, Goodluck Jonathan, condemned the killing of the hostages and said in a statement that "the perpetrators of the murderous act, who have all been arrested, would be made to face the full wrath of the law". It remained unclear last night how many arrests had been made.

Mr McManus and Mr Lamolinara had been involved in the construction of the state headquarters for the Central Bank of Nigeria. They had been working for B Stabilini, an Italian construction firm based in the Nigerian capital, Abuja, when they were kidnapped on 12 May 2011 from their apartment in Birnin Kebbi city. Another Italian employee managed to escape during the kidnapping but a Nigerian neighbour who came to help was shot and wounded.

A video was released showing a blindfolded and bearded man in an orange vest, with three men in dark clothing behind him armed with rifles and a machete. The hostage, believed to be Mr McManus, called for the British Government to respond to the demands of the group, so they would spare his life.

Mr McManus's family released a statement saying they were "devastated" by his death but thanked those who had worked to try to free him. "During this ordeal we have relied heavily on the support of our family and friends which has never waned and has enabled us to get through the most difficult of times," they said.

"We are also aware of the many people who were working to try and have Chris returned to our family, and his girlfriend. We would like to thank all of them for their efforts. We knew Chris was in an extremely dangerous situation. However we knew that everything that could be done was being done."

In September 2008 two Britons were held by the Movement for the Emancipation of Niger Delta. A Scottish oil worker was abducted and his guard killed in April 2009, in the Rivers State capital Port Harcourt. Three Britons and a Colombian were kidnapped in January 2010 and in November of the same year, four men from the US, Canada and France were seized.