LONDON, July 14 (Reuters) - Sterling extended gains against the euro on Tuesday, hitting the day's high after Bank of England policymaker-desgnate Adam Posen said he expected the UK currency to trade higher against the euro in the medium term.

The euro EURGBP=R slipped to the day's low of 85.78 pence according to Reuters data, down around 0.3 percent on the day, after Posen made the comments before the UK Parliament's Treasury Committee [ID:nPOSEN].

Before the statement, the euro traded around 85.90 pence.

(Reporting by Naomi Tajitsu)