A council leader has urged the Prime Minister to act immediately and start minting medals promised for Second World War Arctic convoy veterans before it is too late for some of the elderly recipients.

Gerald Vernon-Jackson, the Liberal Democrat leader of Portsmouth City Council, has written to David Cameron calling on him to award the medals as soon as possible before any more veterans die.

More than 3,000 seamen died over four years from 1941 on missions to keep open supply lines to Soviet ports which were dubbed the ''worst journey in the world'' by Winston Churchill.

The vital service was not recognised with a medal and the veterans were unable to lobby for honours after the war because Russia became an enemy.

But in December, Mr Cameron told the Commons he had accepted an expert review's recommendation that an Arctic star medal should finally be minted.

He said: ''I am very pleased that some of the brave men of the Arctic convoys will get the recognition they so richly deserve for the very dangerous work they did.''

In his letter, Mr Vernon-Jackson said: ''I would like to thank you for the decision of the Government to allow the awarding of the Arctic convoy medals.

''I am very conscious that the veterans who will receive these medals are becoming increasingly old.

''It is now 73 years since the convoys and therefore veterans are very elderly. Every week before the award of the medals puts them at risk of not being able to receive the medals they so richly deserve.

''Please could I ask you to use all your endeavours to make sure that the medals are struck and presented with great urgency so that no more veterans come to the end of their lives before being presented with the medals they so richly deserve.''