Only six months after the Falklands war, Britain's Royal Navy is again poised for a confrontation on the high seas. But this time, it is not territory at stake. It is the sprat, a small, tasty sea fish akin to the herring.

Proclaiming "Viking stubbornness" as his credo, a Danish skipper, Kent Kirk, is guiding a wind-tossed 140-ton trawler toward the sprat catch inside Britain's coastal waters off Newcastle. Awaiting him is the full force of 22 vessels in Britain's fisheries protection squad, some armed with small artillery, two surveillance aircraft and Royal Air Force Nimrods.

Kirk intends to get arrested--he says he will submit peacefully--to test new British restrictions on fishing imposed by Britain Jan. 1 after Denmark, alone among members of the European Community, refused to accept a common fishing policy.

The Danish government urged fishermen to avoid a full-blown fracas with the British while efforts at a compromise continued. But Kirk, a politician representing a fishing district, set off anyway and should arrive early Thursday.

To assure that his efforts do not go unheralded, Kirk has loaded his trawler and an accompanying one with reporters and photographers. But the gale-force winds and rough seas off Britain's northeastern coast have made the undertaking something less than a pleasure cruise.

In fact, it is not altogether easy to regard the looming confrontation over sprat hoarding as an issue of great consequence. The Guardian today dismissed Kirk as a "publicity seeking sea dog." There is no likelihood, for instance, that shots will be fired, as they were in 1975 when Iceland extended its territorial waters to 200 miles, excluding British fishermen and precipitating what became known as the "Cod War."

Yet, the EEC fishing dispute has been dragging on for a decade--as long as Britain has been a member of the European Community--and is an emotional question to the tens of thousands of fisherman whose livelihoods can be affected by the outcome.

The problem is how to apportion fish quotas within the 200-mile zone that the community has determined as its general territorial waters. About two-thirds of the zone would be British if there was no European Community so British fishermen--their horizons narrowed by exclusion from places like Iceland--want a substantial share of the catch in their immediate coastal waters.

Finally, a deal was struck giving the British an edge over other countries, although not as much as originally sought. Everyone agreed, including the Danish minority government, but not its fishermen, who got the measure blocked in parliament. The Danes wanted a bigger bite of the mackerel found off Scotland and around the Shetland Islands.

When the Jan. 1 deadline for a new fishing policy passed, the other countries adopted it despite Denmark's demurral. That means that Kirk could get a maximum fine of $80,000 and have his fishing gear confiscated if he breaches a 12-mile coastal barrier for the sprats he seeks.

Other Danish trawlers have been spotted in the area since Saturday, but none has violated the complex regulations on how many commercial fish--like sprats and mackerel--can be caught and how many of the industrial variety to be used as animal meal or fertilizer.

Kirk believes that once convicted in a British court--which he is bound to be--he can take the case to the European Court of Justice in Strasbourg and challenge the new rules on technical grounds. Kirk, a member of the European Parliament, may be correct, experts say, in spotting the possibility of legal loopholes in the new regulations.

Meanwhile, the word from the Royal Navy is that Kirk is awaited with cool--if not frigid--determination by the fishing protection force. When he arrives, he will be taken without fuss into port and formally charged. "I think the Royal Navy will do their job," Kirk said this afternoon by radiophone, "just as we are doing ours."