Rural groups have warned the government of the potentially-disastrous consequences of further alienating Britain from the rest of the European Union.

In particular, they highlighted benefits Norfolk gets from EU agricultural and conservation subsidies, which were due to channel more than �28million to 421 recipients in the county last year.

Their comments came as tentative steps were taken by diplomats to see if UK relations with other European nations could be repaired after David Cameron became the first British prime minister to veto an EU treaty earlier this month.

Relations deteriorated further following the veto when senior French ministers began criticising the British economy, as parts of a resurgent Conservative right-wing have led calls for Britain to leave the EU altogether.

But among those warning caution was Norfolk Wildlife Trust which received �1.9m in European subsidies last year – the biggest amount given to any single recipient in the county.

Chief executive Brendan Joyce said: 'The impact of pulling out of the EU would presumably be no environmental stewardship schemes, no single farm payment and no EU structural and development funds.

'This would be disastrous for farming and nature conservation. It would be disastrous for the marine environment and for fisheries stocks.'

It was at the EU Summit in Brussels on December 9 that Mr Cameron vetoed the formation of a treaty designed to bind eurozone states into tighter financial integration.

Mr Cameron argued the treaty would have been damaging to the British economy as it contained no safeguards for UK financial services, but his critics have accused him of pandering to the Euro-sceptic wing of his party. The prime minister suffered a politically embarrassing rebellion earlier this year when 81 of his MPs defied his will and voted in favour of holding a referendum of Britain's membership in the EU.

However, the National Farmers Union (NFU) also voiced caution over allowing Euro-sceptic elements of the Tory party to hold sway over government policy.

NFU director of policy for England and Wales Martin Haworth said: 'If the Euro-sceptics do manage to get some traction it is worth noting that there is a potentially very damaging scenario for British agriculture.'

He warned that Mr Cameron's use of the veto could marginalise the UK in trying to push through any reform of the Common Agricultural Policy and broader regulation. He added: 'It is clearly in everyone's interest to see the uncertainty in the eurozone resolved as soon as possible.'

Foreign secretary William Hague met his German counterpart Guido Westerwelle. They agreed to identify 'urgently' new initiatives to take forward the single market.