Health campaigners lauded a historic low in teenage pregnancy yesterday but warned that government cuts will soon send the numbers rising again.

Data from the Office for National Statistics revealed the rate of conceptions among women aged 15-17 fell to 3.83 per cent in 2009. This was a decline of 5.9 per cent on the previous year's figures, and was the lowest level for almost 30 years.

However, two experts in the subject claimed that the rate will inevitably begin to increase again if reductions in sexual health services are carried out.

Simon Blake, director of the sexual health charity Brook, said that while the figures demonstrated the amount of work that has gone into reducing teen pregnancy during the past decade, the Government's cuts are "short-sighted".

"We strongly urge the Government to ensure a continued local and national focus on teenage pregnancy as we know that if we stop focusing on delivering sexual health services the rates will go up," Mr Blake said. He added that further investment would in fact save money, claiming "for every £1 spent on contraception, £11 is saved".

His views were echoed by Gill Frances, former chair of the Teenage Pregnancy Independent Advisory Group. said: "We are currently experiencing major cuts in teenage pregnancy work around the country which will halt progress and push up the rates again.

"The data for this year won't be out until 2013 by which time a lot of the fantastic work that was under way will have been shut down.

"We urge local councils and primary care trusts (PCTs) to think strategically now and prioritise teenage pregnancy reduction, which is cost-effective and reduces critical problems such as child poverty and health inequalities."

The subject of teen pregnancy has been a particularly contentious one in recent years. When a 13-year-old apparently became a father two years ago, Iain Duncan-Smith highlighted the case as evidence of "Broken Britain," saying it highlighted "the complete collapse in some parts of society of any sense of what's right and wrong". A DNA test later revealed that another boy, aged 15, was the real father.

A year later the Conservatives were accused of being "out of touch" after wrongly claiming that 54 per cent of girls in the most deprived areas of the UK become pregnant before they turn 18. The figure was in fact 5.4 per cent.

Children's Minister Sarah Teather welcomed the ONS figures yesterday, but said there was "still much more to do, to further reduce the number of teenagers whose lives are changed forever by an often unwanted pregnancy."

She added: "There remains a huge variation in the progress that has been made in reducing teenage pregnancy rates across the country.

"Some local authorities have seen their rates decline by up to 45 per cent while others have struggled.

"It is important, therefore, that local areas learn from each other and share what has worked, so that they invest in the things that will really make a difference."

The figures also indicated that the rate of women over 40 falling pregnant has almost doubled in the past 20 years, rising from 6.6 per 1,000 in 1990 to 12.8 in 2009.