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By John Geddie and Dhara Ranasinghe
LONDON, June 20 (Reuters) - Another snap election in Britain could prove negative for the country's credit rating, S&P Global said on Tuesday, adding that it may not wait before Brexit terms are known before taking more rating action, likely to be another cut.
S&P stripped Britain of its coveted triple-A rating after the Brexit vote last June, downgrading it by two notches to AA and assigning a negative outlook.
A year on, inconclusive national elections have raised the prospect of another ballot in 2017, which S&P's sovereign ratings chief Moritz Kraemer said would be negative for the rating if it delayed Brexit negotiations.
"There is no time to be wasted," said Kraemer. "If we have another hiatus with Brussels because of an election campaign going on, then that in itself would, all other things being equal, be negative."
Brexit negotiations started this week and need to be wrapped up before the formal divorce in March 2019.
Asked if S&P would wait until the end of the Brexit negotiations to take another ratings action on Britain, Kraemer said: "No, we don't have to wait."
"We will review the UK every six months... and if necessary more often... We will be watching the economic implications, the implications for the public finances, the constitutional implications like the whole Scotland situation... and things like the currency and if it will maintain its reserve status."
Kraemer, speaking on the sidelines of a Euromoney conference in London, said the next rating action would most likely be a cut because of the negative outlook.
Kraemer earlier told an audience that "the stakes are extremely high" for Brexit and the the risks "more tangible than we see in Europe or the U.S".
The Brexit strategy debate within Britain's government has been opened up again by Prime Minister Theresa May's unexpected failure to win a parliamentary majority in the June 8 ballot.
Some analysts have argued a likely tie-up between her Conservatives and the DUP could ensure a softer stance because the small northern Irish party will not support a deal that creates a hard border with its Republic of Ireland neighbours.
But Kraemer said this uncertainty over the government's stance only raised the prospect for negotiations finishing with no deal - the most economically damaging outcome.
"With dependence on the DUP, a customs union is becoming a bit more likely...But if we have a customs union then that means Britain cannot strike trade deals with other countries and that might create controversy with some in the Conservative party.
"It might just come to nothing, that is the risk. That is how a hard Brexit would come about and we think that would be very detrimental for the UK economy." (Reporting by John Geddie and Dhara Ranasinghe; Editing by Jeremy Gaunt)