The UK is to boost its military satellite communications with the launch of the Skynet B spacecraft.

The launch was scheduled for today but has been put back until at least Monday after technical problems with its fuel system.

Once deployed, the craft will work alongside Skynet A, which successfully launched in March and is now providing support to troops in Iraq and Afghanistan.

The £3.6bn Skynet project is the most expensive in the history of the UK's space programme, involving widespread upgrades to military vehicles to allow communication with the satellite system.

The satellite will be operated on behalf of the Ministry of Defence by Paradigm Secure Communications.

"We are all very excited about the launch of Skynet 5B," said Malcolm Peto, managing director of Paradigm.

"The programme continues to deliver success and is an excellent example of what can be achieved with co-operation between industry and the Ministry of Defence."

Skynet B was due to be transported by a rocket from Kourou spaceport in French Guiana, launching at 10.04pm GMT on Friday. But further tests will now take place before a decision is made on rescheduling.

Paradigm is part of EADS Astrium, the aerospace division of the European Aeronautic Defence and Space Company.