Caretaker Prime Minister Thaksin Shinawatra casts an advance vote yesterday for the Senate election before leaving for London.

Thai Rak Thai Party leader Thaksin Shinawatra has found a way out of the political impasse that would be caused by a failure to fill all 500 seats in the House of Representatives by the legal deadline, a party source said.

His caretaker administration is likely to cite certain clauses in the Constitution that empower it to seek royal command for the House to convene if there is a "disorder" in governing the country, according to the source. The need for solving the national problems would be cited.

With the clauses in question cited, a new House could convene even though not all the House seats were filled, said the source.

Time is running out for the Election Commission to complete the election by 30 days after the April 2 polls. The deadline ends on May 1.

The possibility that the 500 House seats may not be filled remains high. Many candidates from the ruling party will again have to overcome the hurdle of winning at least 20 per cent of votes from the constituents in the provinces where they were far below the minimum in the April 2 voting.

Thaksin left for London yesterday after casting an advance ballot for next week's senatorial election.

"I'll take this chance to relax and meet old friends. I want to take a break. I'm getting old," he told reporters before heading to Bangkok's international airport.

When asked if he would hold talks with British Prime Minister Tony Blair, Thaksin said, "I'll meet with familiar leaders. We could possibly have some coffee. But my meeting is unofficial. It has nothing to do with politics or business."

One of Thaksin's daughters, Pinthongta, is studying in London.

Earlier this week, a source told The Nation that Thaksin is seeking a meeting with Blair and leaders of some of the other countries he planned to visit. The proposed meetings have caused discomfort in the diplomatic community, as Thaksin's political status is still unclear.

After his stop in the UK, Thaksin said he would fly to the United States to visit universities in Kentucky and Texas where he received a master's degree and a doctorate in criminal justice.

He will return to Bangkok on April 19 and attend a meeting of his party on April 24 before flying to China and Japan later in the month, he said.

"I will travel more as many countries have invited me to give lectures on economics and how to solve economic problems," he said.

On April 4, Thaksin announced he would step down as prime minister despite his party's victory in the April 2 election, which was boycotted by the main opposition parties.

He chose his top deputy and caretaker justice minister, Chidchai Vanasatidya, to serve as acting premier until a new prime minister is named.

Thaksin hit back at Democrat Party deputy leader Surin Pitsuwan, a former foreign minister, for his comments on his trips. Surin had called Thaksin's trip a "political ploy".

"[Surin] should allow the right side of his brain to work a little bit more in order to make more creative comments. He should use his free time during the Songkran holiday to take a rest and make more creative comments for the sake of the country," Thaksin said.

Several ministers gathered to see their leader off at the airport including Chidchai and Deputy Interior Minister Sermsak Pongpanit who is expected to follow Thaksin to London on Monday. Deputy Prime Minister and Industry Minister Suriya Jungrungreangkit, Transport Minister Pongsak Ruktapongpisal, Social Development and Human Security Minister Watana Muangsook, Natural Resources and Environment Minister Yongyuth Tiyapairat and Foreign Minister Kantathi Suphamongkhon were also on hand to wish Thaksin farewell.