Britain's National Oil Corp. is under mounting pressure to cut prices from some major buyers of its North Sea oil, but it hopes to resist any reduction until after Middle Eastern producers have taken the lead.

While oil analysts here say a cut is inevitable, they add that Britain's strong preference is to avoid being held responsible for starting a round of international price-cutting. They also say that London would not like to see an unrestrained downward spiral, which could lead to international financial instability and discourage additional North Sea oil development.

"Britain wants a stable descent in prices," one expert said today.

The British are hoping that Arab oil producers in the Persian Gulf, led by Saudi Arabia, will cut prices first. Reports from the area suggest that the Saudis and Kuwait soon could cut as much as $4 a barrel from the official price of $34 unless the Organization of Petroleum Exporting Countries agrees on production ceilings.

"This is a slow bicycle race," said a senior British official, describing the government's reluctance to emerge as a price leader. Once the market has stabilized, he said, Britain will adjust to its consequences.

The Soviet Union reduced the price of oil sold to northwestern Europe by $2.18 a barrel to $29.35 a barrel in the first price cut by a major oil producer since last week's OPEC meeting failed to agree on production and pricing, United Press International reported.

In a separate development, United Arab Emirates Oil Minister Mana Saeed Oteiba denied a Kuwaiti news agency report that the emirates, Saudi Arabia, Kuwait and Qatar planned to cut prices by $4 a barrel if OPEC remained deadlocked, UPI said. Oteiba told reporters that the gulf states have not made a decision on prices.

Britain's pricing plans have taken on unusual significance since an OPEC meeting broke up in disarray nine days ago, the second time in two months. As the world's fifth largest oil producer and a direct competitor with key OPEC member Nigeria, Britain would have a considerable impact on other suppliers by cutting prices.

Saudi Arabian Oil Minister Sheik Ahmed Zaki Yamani predicted after the unsuccessful OPEC session in Geneva that Britain would be the first important exporter to cut its price, now at $33.50 a barrel, and said that London might go down by as much as $3 within days.

Yamani hinted at Geneva that OPEC's $34 price was too high, and some industry analysts suggested that the Saudis were hoping that Britain would lower prices so that a non-OPEC member would bear the stigma of being the first to go down. The Cyprus-based oil industry publication Middle East Economic Survey, which is considered close to the Saudis, said that the Saudis and their Arab gulf allies would accept a $4 price cut for their own crude.

The principal reason for the downward pressure on prices is the oversupply of oil on world markets. Some buyers of North Sea output have warned in recent days that they will reduce or halt purchases under long-term contracts if the price is not lowered, according to Michael Unsworth, an analyst with the firm of Scott, Goff, Hancock.

A cutback in purchases would force the government-owned BNOC to unload substantial inventories on the spot market, or the market for oil sold outside of long-term contracts. Spot-market prices have declined since the Geneva meeting, lowering the spot price for Saudi Arabian light crude to about $29.50 a barrel.

The names of the buyers who are seeking North Sea price cuts have not been released, Unsworth said, and negotiations with BNOC are continuing. It is understood, however, that British Petroleum and Shell, the two largest North Sea companies, are not among those pressing for an immediate cut.

As a result of its oil exports, Britain maintains a substantial balance-of-trade surplus--a decided plus for an economy suffering from severe unemployment and continuing decline in manufacturing industries.

A fall in oil prices, even to as low as $25, would not severely affect the country's revenues, according to analysts. Oil bills are paid in dollars, and the 12 percent slide in Britain's pound sterling against the dollar since last November already has increased the number of pounds that London receives per barrel of oil.

"While government revenues from oil would not be as high as some forecasts," said Unsworth, "they would certainly continue to be satisfactory."

Moreover, the drop in oil prices would probably have an overall beneficial effect by encouraging an end to the international recession. Britain has "far more to gain from a more prosperous world economy," Samuel Brittan, one of the country's leading financial analysts, wrote this week, "than it stands to lose on balance-of-payments or Treasury revenue accounts."

The dangers of a free fall in oil prices would be in the possible impact on Britain's banks with large outstanding loans to some oil producers. A permanently low price for oil also might discourage further development of North Sea fields, whose output will start to decline in the late 1980s unless further exploration succeeds.

Ironically, for all the anticipation of falling oil prices, the cost of gasoline at the pump to consumers in Britain is rising as a result of sterling's recent fall against the dollar. A British gallon now sells for about $2.70, and oil companies say the price may go higher.