A Royal Navy speedboat this morning chased off a Spanish Guardia Civil boat after it reportedly cut across the path of a US Navy vessel visiting Gibraltar.

The rigid-hulled inflatable boat intercepted the Spanish patrol boat, Rio Belelle, after it sailed in front of the transport vessel USNS Carson City, Mailonline reported.

The Foreign Office in London played down the incident, but one witness said the Spanish vessel had been “irresponsible and reckless”.

Michael Sanchez, founder of Gibraltar Coast Watchers, said: "Nothing better to ruffle Spain's feathers than a visit of a US Navy ship to Gibraltar."

Naval sources said the Spanish incursion appeared to have been a deliberate provocation.

One source said: "The expectation is that the smaller boat would keep out of the bigger ships way in the approaches.

"There are rules about who gives way to what and it looks like this was done to provoke a reaction."

Gibraltar's government refused to comment on the incursion, but regularly accuses Spain of trespassing in its waters.

A Foreign Office spokeswoman said the Spanish passage through Gibraltar’s waters was innocent and there was no risk to safety.

She said: “As is routine, the vessel was shadowed by the Royal Navy.”

Gibraltar was captured by Britain in 1704 and ceded in the 1713 Treaty of Utrecht, but has long remained a dispute between London and Madrid.