Property group Grosvenor has warned it expects "significantly weaker" returns in 2017 as it battles against a slowdown in the London market.

Grosvenor - which owns a raft of properties built on the Grosvenor family's traditional holdings in Mayfair and Belgravia - said revenue profit, which is an underlying measure of growth, fell 5% to £79.2 million in 2016.

The London market cooled substantially last year as it was hit by uncertainty surrounding the Brexit vote and higher stamp duty on purchases.

The group said total returns of 8% were better than expected, despite being down on the 9% seen in 2015, as it was boosted by its international operations.

Just under half of its assets are now held outside the UK as part of efforts to diversify overseas.

Mark Preston, chief executive of Grosvenor Group, said: "Strong performance from Indirect Investment (used by the group to invest in other property companies) and our operating companies in North America and Asia, significantly boosted in sterling terms by its depreciation against other currencies, offset cooling market conditions in London."

He warned: "Looking ahead, we expect our returns in 2017 to be significantly weaker due to limited room for market value appreciation and a reduction in revenue profit following some well-timed disposals."

Grosvenor said the value of its total assets under management fell to £12.7 billion in 2016 from £13.1 billion in 2015.

The group's former chairman - the sixth Duke of Westminster, Gerald Cavendish Grosvenor - died last August.

His title was passed down to his son, Hugh.