Gordon Brown is under mounting pressure to boost Britain’s long-term military presence in Afghanistan after the army suffered a surge in fatalities in Helmand province.

Following the deaths of 15 British troops in the province in the past 12 days – the worst setback for the UK in Afghanistan in the past three years – army chiefs are set to urge a rise in British troop levels from 8,300 to 9,000 in November if the campaign is to be properly resourced.