Mr Kaczynski, whose brother Lech is President, will accentuate the country’s status as one of the most awkward members of the European Union. In an inaugural speech yesterday he promised to make Poland a big country that would count in Brussels while protecting its culture and morals against EU liberalisation.

Marriage should remain a union between a man and a woman, he declared. “We won’t let ourselves say that black is white,” he said. “We are going to protect this foundation of social life.”

Homophobic, intolerant, ultranationalist and always eager for a scrap with Poland’s neighbours, the twins are sending alarm bells ringing in and out of the country.

“He will be a bad Prime Minister,” Donald Tusk, the leader of the opposition Citizens’ Platform, said, “and he will have an unprecedented concentration of power at his disposal.”

The former President and Solidarity leader Lech Walesa, who was once advised by the twins, described them as polarisers with a destructive energy. He said: “I didn’t like their conspiracy theories. They were always suspecting people, always involved in intrigue.”

To reduce confusion Lech Kaczynski did not appear yesterday in the presidential chair to cheer on his brother. The prospect of television cameras swivelling between the two men would have detracted from Jaroslaw Kaczynski’s moment of glory. Jaroslaw Kaczynski has been sensitive about world reaction to twins taking over the running of a country and since last autumn has resisted offers to become Prime Minister. Look-alike rulers have occurred only in fiction, such as Antony Hope’s The Prisoner of Zenda or in Hollywood films.

On the face of it the blueprint for Poland that Jaroslaw Kaczynski presented to parliament was a sensible centre-right programme. To reduce Polish dependence on Russian oil and gas he favoured nuclear energy development and was counting on the supply of Norwegian gas.

To retain a strong Polish currency he pledged to cap the budget deficit. He also promised to reduce the housing shortage and combat unemployment rates of 22 per cent.

Yet the twins, 57, are famed for their fractiousness. Jaroslaw Kaczynski, deploring the declining Polish population, made it clear yesterday that Poland would remain hostile to abortion. And critics had no doubt that his Government would seek to exclude homosexuals from the teaching profession.

Lech Kaczynski ordered the police to break up a demonstration by gays during his tenure as Mayor of Warsaw, declaring: “I have nothing against them protesting as citizens, only as homosexuals.”

That sentiment was shared by his brother. Indeed, the views of the new Prime Minister and the President are so similiar that they often finish each other’s sentences. The only way to distinguish them is by a small mole to the left of Lech Kaczynski’s nose and the cat hairs on Jaroslaw’ Kaczynski’s clothes.

Lech is married with a daughter, but his brother lives with their mother in a house full of cats. Their mother, Jadwiga, a retired professor of literature, shaped their politics.

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