by political editor Paul Francis

Extra money raised by hiking Dartford Crossing tolls will not be used to pay for improvements to it, ministers revealed today.

The government is to increase tolls to £1.50 next year and to £2.50 by 2012 as part of its spending review aimed at curbing the national deficit.

The price hike has angered motorists and road user groups after successive governments pledged the tolls would be scrapped once the bridge was paid for.

Transport minister Mike Penning said there were no plans to ring-fence income from the increased charges to improve the crossing as some of the money was already being used to do so.

Instead, it looks like additional cash will be invested in other transport initiatives.

The minister was responding to a written question from Labour backbench MP John Woodcock, urging the government to set aside some of the money raised from the higher charges to fund improvements to ease congestion and delays.

In his reply, Mr Penning said: "Income from road user charges at the Dartford Crossing are already ring-fenced for investment in transport, including improvements to the crossing.

"We have no intention to further ring-fence such income."

He added: "We have made clear that investment at Dartford is an absolute priority, and increasing the charges as proposed, allows for future investment at the crossing, including the implementation of free-flow charging technology, and to help fund proposals for a new, additional crossing."

Crossing charges raise about £17m a year and is used to pay for improvements to the national transport network.