MPs have voiced alarm over the ballooning cost of two pioneering Oxfordshire science projects.

The Diamond Synchrotron and the Isis Neutron Source, both on the Harwell science and innovation campus outside Didcot, are listed as over budget by the Commons public accounts committee.

Its report says the Diamond super microscope project, the first phase of which was completed in January, will cost £383.2m - £30m more than previously forecast.

The annual running costs for the scheme, which enables scientists to use powerful light beams to study the structure of matter to support the battle against disease, have also soared, from £24.4m to £46.1m.

The capital costs of the Isis Neutron Source's Second Target Station have shot up by nine per cent, from £133.1m to £145.6m. It is due to be completed next October - a month behind schedule. The expected running costs have also rocketed, from £5.4m to £9.9m per year. Most of the money for the projects is coming from taxpayers.

Edward Leigh, the committee's chairman, said: "Exciting new scientific facilities are now coming on stream and I do not doubt their work will help to keep Britain among the leading centres of research and discovery.

"But the teams who plan and take forward these projects must have the project management expertise and commercial skills to deliver them to time and budget."