BDO has announced a £283m turnover figure - a drop of 0.6% from last year's £284.7m - while operating profit in its annual results took a 12% hit, going down to £51.2m on the back of the firm's merger with PKF.

The merger - expected to be completed by spring - will wipe out PKF's brand in the UK and bolster BDO's presence creating a firm with nearly £400m in fee income in sixth position, nipping at the heels of Grant Thornton which this year announced a fee income of £417m.

The firm's fee income for the financial year ended 29 June 2012 was helped by a 5% growth in audit fee income, to £96m. BDO said that this was also boosted by investment in financial services expertise - with the hireing of three new financial services partners.

The firm however saw a dip in fee income for tax work - tax income dropped 2.9% to £80m - despite the growth it says it experienced in work relating to private clients and expatriate work for both domestic and international clients.

Advisory work also declined - dropping 4.5% to £107.1m as a result of lower levels of corporate transactions.

The firm's 196 partners managed to maintain their individual fee per partner at £1.4m, with profitability at £261,224.

Simon Michaels, managing partner, BDO LLP said the firm's strategy has been to prioritise investment in long-term growth and quality to establish a financially strong business for clients and its own staff.

'We are leading our industry in client service and have a strong balance sheet which will support continued investment. We are also part of a thriving international network, recently breaking the $6bn income mark. This means we're starting 2013 in a good position with an exciting year ahead. Our merger with PKF reinforces our ambition to lead the mid-market from this position of strength,' said Michaels.