UPDATE 4-Pound hits 31-year low on "hard" Brexit worries while UK stocks soar
* Sterling down to lowest level vs dollar since mid-1985
* Pound's weakness gives lift to UK stocks
* FTSE 100 closes up near 2015 record highs
* FTSE 250 mid-cap index touches new record highs
* Pound's slump has hit dollar value of UK shares (Adds fund manager quote, details)
By Anirban Nag and Sudip Kar-Gupta
LONDON, Oct 4 (Reuters) - Sterling slid to its lowest level in more than three decades on Tuesday on fears of a "hard Brexit" from the European Union and its single market, although the weaker pound sent UK stocks surging higher.
The pound has already lost 1.7 percent against the U.S. dollar since Prime Minister Theresa May said on Sunday the formal process to take Britain out of the EU would start by the end of March 2017.
On Tuesday, she added the divorce from the EU will not be "plain sailing" and there would be "bumps in the road". Continuación...