LONDON, June 11 (Reuters) - British Prime Minister Theresa May was on Sunday seeking a deal with a small Northern Irish party that she needs to stay in power after a disastrous election destroyed her authority days before Brexit talks are due to start.

Mays grip on power was tenuous after she gambled away a parliamentary majority in an election she did not need to call. Conservative Party loyalists urged her to change her leadership style, while critics talked about her days being numbered.

Theresa May is a dead woman walking. Its just how long shes going to remain on death row, former Conservative finance minister George Osborne, who was sacked by May when she became prime minister last year, told the BBC.

The Conservatives won 318 House of Commons seats in Thursdays election, eight short of an outright majority. Labour, the main opposition party, won 262.

Labour leader Jeremy Corbyn said he could still be prime minister, although his party has no obvious way to build a majority coalition. He said a new election might be necessary later this year or early in 2018.

The political turmoil comes a week before Britain is due to start negotiating the terms of its exit from the European Union in talks of unprecedented complexity that are supposed to wrap up by the end of March 2019, when Britain actually leaves.

That timeline now looks even more ambitious than before, not least because Mays electoral debacle has emboldened those within her own party who object to her hard Brexit approach of leaving the European single market and customs union.