Grosvenor and the Canadian Pension Plan Investment Board are under offer to buy the first asset in their Central London office joint venture, PropertyWeek.com can reveal.

The Duke of Westminster’s property company and the giant Canadian investment fund are under offer to buy Lacon House in Midtown for around £95m from RREEF, in a deal that represents a yield of around 8.5%.

The duo formed the joint venture in July last year, with a view to buying offices with asset management opportunities in the capital. CPPIB is putting up £190m of equity and Grosvenor’s fund management arm £10m.

The 215,000 sq ft Lacon House fits the bill, in that the only tenant, law firm Nabarro, is currently weighing whether to exit the 118,000 sq ft it currently occupies at the building. It is weighing whether to move to Alan Gate, where JP morgan is currently sub-leasing space.

Its lease expires in 2014, and the value of the building could be increased by either persuading Nabarro to stay, or refurbishing the building and leasing the space.

Jones Lang LaSalle is advising RREEF. All parties declined to comment.