HSBC says Brexit could knock 20 pct off sterling, 1.5pp off UK GDP growth

(Corrects first paragraph to make clear sterling could fall up to 20 pct)

LONDON, Feb 24 (Reuters) - Sterling could lose up to 20 percent of its value and UK economic growth could be up to 1.5 percentage points lower next year if Britons vote to leave the European Union in the June 23 referendum, HSBC said on Wednesday.

"A vote for Brexit would have potentially huge consequences for all asset classes. Following a vote to leave we think uncertainty could grip the UK economy, triggering a potential slowdown in growth and a collapse in sterling," they wrote in a note.

They reckon sterling could fall 15-20 percent against the dollar towards the lows of the mid-1980s, meaning it would move towards parity with the euro. On Wednesday sterling was trading below $1.40 for the first time in seven years and the euro was trading just under 79 pence.

The plunge in sterling could push inflation up by 5 percentage points, and growth could be 1-1.5 percentage points lower, roughly halving the bank's current 2017 growth forecast of 2.3 percent.

The hit to growth could be even more severe if the Bank of England raises interest rates to counter the sharp fall in sterling, they added. (Reporting by Jamie McGeever; Editing by Nigel Stephenson)