London — Escalating rhetoric. Deep doubts about sanctions. Regretful realism. Close contact with allies. Deep concern about the next few weeks. These factors make up the emerging British government reaction so far to the Polish crisis. Britain represents a middle NATO Alliance view - softer than the hard-line attitude of President Reagan, but harder than the public caution being shown in West Germany.
In homes, factories, and offices around the United Kingdom this holiday season, hearts go out to the Polish people.
''We have so much,'' said one Surrey housewife as she sat by a coal fire with her family. ''They have so very little. All of us should be praying and helping as much as we can.''
Meanwhile, the British Broadcasting Corporation (BBC) has stepped up its normal three-hour-a-day broadcast to Poland by an extra 45 minutes of news each day.
At a subdued No. 10 Downing Street, residence and home of Prime Minister Margaret Thatcher, and in the cavernous Foreign Office across the road, strong efforts are made to orchestrate public statements with NATO allies and to stay in step with the United States.
Mrs. Thatcher's rhetoric has sharpened in the past week as she has consulted with Bonn, Paris, and Washington. Initial caution has been replaced with statements such as, ''almost every article of the Helsinki agreement is being flouted.''
Where Britain differs from the US - on sanctions against Moscow, for example - policy is to play up cooperation and play down doubts.
In fact, British policy is not following the US over new food aid to Poland. British food aid continues, even though no one here has solved the riddle of sending in food to the people so that it is not intercepted by the Polish Army or security forces.
(In 1980-81, Britain has provided Poland with 477,500 tons of barley, 10,000 tons of butter, and 3,000 tons of beef. Of a remaining 40,000 tons of barley, 10 ,000 is being shipped, and the rest awaits indications it can get through safely.
(Britain has decided in principle to continue its (STR)30 million ($57 million) aid to the Ursus tractor plant. London has agreed to postpone Polish debt payments in 1982 as it has been willing to do in 1981.)
''The fact is,'' says one source close to No. 10 Downing Street, ''that there isn't a lot we can really do.''
There is deep wariness here over the usefulness of sanctions, whether fishing , maritime, agricultural, export, or technological. ''They've been tried in Africa, in Iran, and over Afghanistan,'' the source said, ''with unhappy results.''
Reagan emissary Lawrence Eagleburger was not scheduled to come to London on his mood-sounding European trip. British officials don't reply directly to questions about direct US pressure to join in economic sanctions against Moscow.
''There's ambiguity,'' says the source. ''We know that the Soviets must approve of what the Polish military is doing. But we have no evidence that Moscow itself is militarily involved.''
Another problem: Should the West act now against the Soviets - or wait until, as many here fear, Polish resistance stiffens and the Soviets are tempted to send in their own armed forces.
Britain has stressed close consultation with other NATO allies. Officials acknowledge that a single common Western stand had not been produced at this writing, but insisted that behind the scenes, NATO allies were very much together with each other and with the US.
The only thing stopping stronger public statements, they implied, was the lack of evidence that Soviet troops were involved.