William Waldegrave, the Minister of Agriculture, Fisheries and Food, said that he was determined to ensure the safety of Cornish boats, and a second fishery protection vessel, HMS Alderney, was sent to join HMS Anglesey in the Bay of Biscay.
The new move came as the skipper of the British vessel Charisma was released without charge after his nets had been seized on suspicion that they exceeded the 2.5km length allowed under EU regulations.
Inspectors found that the nets were 153 metres longer than permitted, but were only slightly over the limit when allowance was made for stretching under the weight of fish.
Barrie Ball, the skipper of the boat based at Padstow, Cornwall, criticised the naval boarding party who seized his nets on Friday. He complained that sledgehammers had been used to smash a way into the wheelhouse.
His boat, one of the smallest in the Cornish tuna fleet, was escorted back to Devonport, but after a five-hour investigation by officials of the Ministry of Agriculture, Fisheries and Food, Mr Ball was released.
The Charisma returned to Newlyn fish market by mid- morning yesterday to deliver nine tons of tuna - valued at pounds 14,000 to pounds 15,000 - from its interrupted first trip to the fishing grounds.
Later, he demanded more backing from the UK authorities, which he said should use greater force to thwart the actions of the Spanish who have surrounded British vessels and destroyed nets.
'We are calling for a bit more help,' he said.
'For the protection vessels to do their job and use a bit more force. Fair play down there is no good.
'I can't understand why we were picked on like this when the Spanish were there. They were trying to get somebody nicked for using illegal nets - it wasn't us and it won't be any of the British boats out there in this war.'
Despite the clashes, Mr Ball said he held no animosity towards the members of the Royal Navy. He said: 'The man who smashed down the doors was gutted. He couldn't believe what had happened - it's the first time they'd had to do it to an English vessel.'
Mr Waldegrave yesterday asked the Spanish minister of fisheries to ensure his country's fishermen do not take the law into their own hands.
'British fishermen have every right to engage in the tuna drift-net fishery,' he said. 'The Government will ensure that they can do so peacefully and legally.
'We have shown we enforce the rules properly. This means there can be no possible reason for our fishermen to be harassed or attacked while on the fishing grounds. It is unacceptable that UK- flagged vessels should be prevented from legitimate fishing as a result of harassment or damage by other vessels. We will see that they are not.'
He said the Government was looking at ways of putting back-up nets on fishery protection vessels so that any that are damaged or lost can be immediately replaced.