Britain's weak productivity since the financial crisis should improve and growth should return to its long-run trend, Bank of England policymaker Adam Posen said on Monday.

I believe - and I think you will find if you ask most members of the MPC, they believe - that we are going to get back to the growth trend we were in for the past 100 years, he said in a lecture at Nottingham Trent University in the English midlands.

But productivity growth or underlying growth in GDP may be around 0.2 percentage points less than in the early 2000s, Posen added.

And a lack of access to finance for small and medium-sized businesses might become a bigger problem if not tackled, he said.

Posen was a lone voice on the Bank's Monetary Policy Committee for most of 2011, calling for more quantitative easing asset purchases to boost the economy, but was vindicated when the MPC backed a 75 billion pound restart in October.

These purchases will be complete at the end of this month, and most economists expect the BoE to approve a further 50 billion pounds of purchases in February.

(Reporting by David Milliken; Editing by Tim Castle)