The Conservatives have said that they will review NHS out-of-hours care if they win the forthcoming general election, following the death of a 70-year-old Cambridge man who was given an overdose by an overtired locum.

Shadow health secretary Andrew Lansley said Labour had made a “serious error” by taking responsibility for out-of-hours care away from GPs, adding that a Conservative victory at the polls would see the spotlight turn on GPs again to make them “collectively responsible” for out-of-hours services.

The decision follows the death of Cambridge pensioner David Gray, who died after being prescribed an overdose of diamorphine by German locum Dr Daniel Ubani, who had been flown in to the UK to be on call out-of-hours.

Dr Ubani, who was working for private healthcare provider Take Care Now, has said that he was overtired when he treated Mr Gray.

Primary care trusts are currently responsible for providing out-of-hours care services by employing private companies or co-operatives to fill in for GPs.

The British Medical Association is expected oppose Conservative plans, as changes to GPs’ contracts were made after doctors complained that they were overworked and underpaid.