Image: NASA GPS Satellite
Britain has told the EU that shutting it out of the Galileo satellite navigation project will cost Brussels hundreds of millions of pounds and cause years of delay.
London has threatened to launch its own version of the system if the EU does not change its stance, according to a document issued by the Department for Exiting the European Union.
The document also makes clear that the UK will seek to have the £1 billion it has already invested in the project - a rival to GPS - refunded if it withdraws from the venture.
Britain has rejected the EU's view that it cannot remain a full member of the project after Brexit as London insists it is in the interest of both sides to continue to work closely together on security issues.
Brussels has made it clear that the UK cannot access the same encrypted Galileo information as EU members, or be involved in its development post-Brexit.
Excluding the UK from full participation in Galileo will cost the EU one billion euro (£880 million) and set the project back by three years, the document states.
The paper said that the position adopted by Brussels "risks being interpreted as a lack of trust" in the UK.
"The UK... has a strong objection to its ongoing exclusion from security-related discussions and exchanges pertaining to the post-2019 development of Galileo."
The paper warns the UK will go its own way if its demands are not met, stating: "If agreement cannot be reached on the future balance of rights and obligations, and UK security and industrial requirements consequently cannot be met, the UK could not justify future participation in Galileo.
"In parallel, the UK is therefore exploring alternatives to fulfil its needs for secure and resilient position, navigation and timing information, including the option for a domestic satellite system.
"The UK wants Galileo to be a core component of the future UK-EU security partnership."
Asked if the EU would repay the UK the £1 billion already invested in Galileo if Britain was excluded from work on the project, European Commission spokesman Margaritis Schinas said: "This issue is being discussed with our British partners, negotiations are ongoing, these are precisely the sort of issues we need to address."
Downing Street said the UK held "constructive discussions" with the European Commission this week on staying in the Galileo project.