London — What does a British prime minister do when the pound is sinking toward its lowest level ever against a rampant dollar, mortgage rates go through the roof, North Sea oil prices drop, and the dockers find cause to join the miners and call a national strike?
If you're as resolute as Prime Minister Margaret Thatcher, you decide it's going to be business as usual and you stay as calm as possible in the hope that confidence at the top will steady the wild gyrations of the world money markets.
This is not only what Prime Minister Thatcher seems determined to do. It is also the kind of unsolicited advice she is getting from many economists who believe that much of the anxiety over Britain's economy is psychological and not a portent of an economy on the skids.
Says Gavyn Davies of the London stockbroking firm of Simon & Coates and a well-known discerner of economic trends: ''There is a crisis of confidence which is self-defeating.''
The basic ingredient for this loss of confidence has been rapidly escalating reports of bad financial news. Add to that a continued miners' strike and the opening up of yet another front of industrial dispute - port operations. All this arouses the public's concerns about labor relations and the possibility of Britain returning to the bad old days of industrial strife.
But until the sudden surge of the dollar, which more than anything is blamed for the battered pound, the British government was taking some satisfaction from the fact that except for stubbornly high unemployment the economy was picking up and was basically sound.
To the Thatcher government, then, it was as though some gremlin had tugged open Pandora's box this past week and let all the economic ills escape at once.
Britain's financial woes have brought loud mutterings from within the rank and file of the Conservative Party, and Mrs. Thatcher has come in for some withering criticism from the press. The Economist magazine, which has been sympathetic to her economic philosophies, has lashed the Thatcher government for its ineptness in carrying out its policies.
The normally unabashedly conservative Evening Standard went so far as to say the economy was ''in a mess.''
Yet given Mrs. Thatcher's temperament (she relishes a challenge) and her strongly ideological approach to the economy, it is thought highly unlikely that she will change her script now.
An astute foreign observer of the British scene says: ''If you ask what the chances are of the zebra changing her stripes, I would say zero.'' In his opinion perseverance on the job had paid off for Mrs. Thatcher. ''It has to be more of the same. It has been for the last five years.''
Whatever the economic vulnerabilities of the country, politically Mrs. Thatcher is in a strong position.
Despite rumblings of discontent among her supporters, her position within the party is unassailable. Her comfortable majority in the House of Commons means she is insulated from the constant threat of political defeat that stared Harold Wilson in the face when he was prime minister back in the 1960s. His razor-thin Labour majority then in the Commons meant he could be defeated at any time in a parliamentary vote.
Not only does Mrs. Thatcher not have to take short-term expedients but also she can use her strong political base to exude the kind of confidence businessmen say is essential now if sterling is to recover.
By the end of last week the pound had made some modest gains against the rampaging dollar.
Although the government is up against the two most militant trade unions in the country - the miners and the dockers - long-time observers of the British scene say the challenge is less serious now than it was a decade ago. The trade union movement lacks the solidarity it enjoyed even 10 years ago and its membership is substantially down. For instance, because of pit closures the number of miners is down from 376,000 in the early 1970s to some 170,000 today.
Back in 1972, when coal miners struck, there was no North Sea oil. Now oil and alternative sources of energy abound, thus minimizing the economic and political clout of the coal miners.
Ten years ago the greatest security threat to the economy from militant workers came not from dock workers or miners but the electrical power workers.
If there was one group of workers who had their hand on the throttle of the nation's economy, it was the electrical power workers. All they had to do was pull the switch. They were willing to play that role back in 1972. Now they are willing to cross any picket line to keep power stations working.
It is a reflection of what has been described as the ''new realism'' within the trade union movement, where confrontation has given ground to economic pragmatism.
There is also a ready appreciation that if the dock strike is not resolved quickly, it could strangle the British economy. Some 80 percent of all Britain's overseas trade goes through its ports.
Even aside from the strikes the prospects for the British economy are not quite so rosy as had once been expected.
According to Tim Baldwin of the London Chamber of Commerce, the quarterly report on the economy that is due out later this week indicates that recovery from the recent recession is beginning to cool.
He says some fundamental trends appear to be emerging. Among them a rise in structural unemployment, a dip in export orders, and an increase in wage pressures which would stoke inflation.
Such concerns are reason enough for the government to hope for a speedy end to the national strikes.