Shearman & Sterling has become the first US firm in London to publish diversity statistics ahead of a controversial requirement from the Legal Services Board (LSB) that will make such reporting compulsory from December 2012.

According to the firm's statistics, men currently make up 80% of the City partnership. Within the associate ranks, meanwhile, there was a more balanced gender split – just short of half of City associates (48%) were female.

Results from the voluntary survey, which saw 73% of all London lawyers and staff participating, indicate 4% are from a black or black British background, with 81% classed as white. 8% of respondents stated that they were from an Asian or Asian British background.

Among partners, 93% were classed as white, while the remaining 7% were from an Asian or Asian British background.

The survey also questioned staff on social mobility. It found 23% of all lawyers and staff were educated at UK independent schools, compared with 14% of partners. 48% of the London office was educated at a UK state school, compared with 36% of City partners.

Meanwhile, 23% of partners taking part in the survey were the first generation in their family to go to university, compared with 29% of associates.

London HR chief Lois Gordon said: "Publishing these statistics is a positive move towards greater transparency and focus on diversity in our London office. As an international practice with a broad and diverse range of clients, we're pleased that the statistics complement and reflect this in terms of the people who work here."

The only other law firms to have released comparable data are Linklaters and CMS Cameron McKenna.

At Linklaters, 78% of UK partners are male, 1% have a disability and 89% are white. Within the associate ranks, the number that are classed as white fell to 74%, dropping to 65% for trainees.

Some 38% of partners were privately educated, dipping marginally to 31% of associates and 34% of trainees.

The results from Shearman's diversity report can be seen here