Turnover in the West End office investment market has tumbled to £972.6m, as stock continues to dry up.

Sales in the first quarter reached £972.6m via 28 deals, compared to £1.8bn in the first quarter of 2012 through 37 transactions, according to research from Colliers International.

The figure was also a sharp drop from the £2.1bn recorded in Q4 2012.

Dominic Amey, head of West End investment at Colliers, said: "The reason for this is not down to the lack of investor appetite, but more so because of the constrained level of supply."

Key deals in Q1, included Peterson Group, advised by Colliers, signing a £121m forward-funding deal for Resolution Property's Ampersand scheme in Soho, W1, and Pembroke Real Estate buying 1 Grafton Street, W1, for close to £80m