Ministry of Defence officials have started preliminary work on a £3billion British satellite navigation system because the UK could be shut out of the European Union’s Galileo network.

The move comes amid a deepening row with Brussels over whether Britain can continue to be trusted with Europe's most sensitive security information in the wake of the Brexit vote.

The Government has already started to take legal advice on whether the Government can recoup the 1.4 billion euros (£1.2 billion) it has invested in the programme since 2003 after being blocked from the most sensitive elements.

Galileo is Europe’s rival to the global positioning system developed and controlled by the US, used by millions of consumer devices around the world in a multibillion-dollar satnav market

Now Gavin Williamson, the Defence secretary, has told The Telegraph that he has ordered experts to start developing plans for a British "sat nav" system.

Mr Williamson has been lobbying EU defence ministers and Nato allies over the EU blocking the UK from Galileo - aimed at pressuring the EU Commission and particularly France.