The EU is to send a "fact finding mission" to the Gibraltar-Spain border to investigate checks imposed on the Spanish side amid continuing tension between the UK and Spain over the issue. The warship HMS Westminster has arrived in the area.
Spanish fishermen sailed into disputed waters off the coast of Gibraltar today to stage a stand-off with Royal Navy boats.
The row is over an artificial reef which Spain claims restricts their right to fish, but Gibraltar says they shouldn't be fishing there anyway.
ITV News reporter Helen Callaghan reports:
It may be a pre-planned training exercise but what timing: UK warships sail through disputed water to Her Majesty's naval base on Gibraltar.
Spain could damage to the economy in Gibraltar, but in doing so it would harm its own, so a further escalation of threats is unlikely.
The PM has said he is seriously concerned by Spain's plans to introduce a levy at the border with Gibraltar.