LONDON, Oct 27 (Reuters) - Britain slashed its planned government bond sales for the current 2021/22 financial year on Wednesday by 57.8 billion pounds, a far bigger drop than forecast by primary dealers. The Debt Management Office cut its 2021/22 gilt issuance remit to 194.8 billion pounds from 252.6 billion pounds, a sharper drop than any of the primary dealers predicted in a Reuters poll that had pointed to a 218.8 billion-pound remit. (Reporting by Andy Bruce; Editing by Alison Williams)