British security officials investigating the Manchester terror attack are considering withholding sensitive information from Washington after a series of damaging leaks they fear are endangering British lives.

Such a move would break with years of increasingly close counterterrorism co-operation between the US and the UK that followed the September 11 attacks. In a sign of the extent of UK concern, Theresa May will raise the issue of US leaks when she meets Donald Trump at a Nato summit in Brussels on Thursday.

The growing controversy over the secrecy of investigators work is threatening to sour relations with the UK’s closest ally as British authorities race to gather intelligence on the Manchester bomber, fearful of a potential second terror attack.