British scientists are secretly working on the design of a revamped nuclear warhead at the Atomic Weapons Establishment at Aldermaston in Berkshire, a short distance away from London [Images], a leading British daily reported on Tuesday.

"The new device, designated the High Surety Warhead, is the British version of the Reliable Replacement Warhead programme which started more than two years ago at the United States military's nuclear laboratories at California and New Mexico," The Herald quoted sources as saying.

In fact, the top-secret project is being run in conjunction with American efforts to build a range of modernised 'failsafe' nuclear firepower for its own submarine-launched Trident missiles, the unnamed sources said.

"The aim (of the project) is to produce warheads which contain fewer degradable components, giving them a longer shelf-life, and to make them so dependable that none would have to be detonated in an underground explosion that would contravene the worldwide test ban," the sources said.

However, a spokesperson for the Ministry of Defence told The Herald, "No decisions on any replacement for Trident have yet been taken and there is no programme to build a successor warhead."

Meanwhile, the British government is in the process of investing almost 2.2 billion pounds in the Aldermaston site to equip it with a state-of-the-art Cray supercomputer codenamed Larch and a laser codenamed Orion to help model nuclear explosions instead of live testing.

The supercomputer, worth 20 million pounds, is so fast that the six billion inhabitants of the planet would have to make 7,000 calculations each per second to keep pace with it, the sources said.

A programme to hire scientists, physicists and engineers is also under way at the 750-acre site.