Given the fees charged by solicitors, a person would be forgiven for assuming that solicitors don’t make mistakes. Unfortunately, this is not the case. The Legal Complaints Service receives more than 17,000 complaints about solicitors a year, and this figure seems to be rising. 
Amongst other things, common causes for complaint include rudeness, unexpected bills, negligence – for instance failure to spot legal problems with a property or missing crucial deadlines – and failing to follow instructions. If you have a complaint, the first step should be to raise your concerns with the law firm concerned and ask for a written copy of their complaints procedure. Most will have a partner whose job it is to handle complaints but, if not, then contact the firm's senior partner.
This can be done by in person, by phone, letter, or by using a resolution form which can be supplied by the Legal Complaints Service, Citizens' Advice Bureaux or sometimes the solicitors' firm.
If making the complaint by phone or in person, be sure to make notes of what was said and in all cases, ask the solicitor to confirm in writing what they intend to do about your complaint and the date by which they will do it.
If this doesn’t get you anywhere, the next step is to contact the Legal Complaints Service within six months of the end of the work that the solicitor did for you (or within six months of becoming aware of the matter of which you care complaining).
The Legal Complaints Service (LCS) is a new organisation that took over responsibility for complaints from the Law Society in 2007. It will initially try and negotiate a settlement between you and your solicitor and, if unsuccessful, investigate your complaint.
It has the power to order the solicitor to reduce your bill, rectify any mistakes and make good any financial loss (up to a maximum of £15,000). It also has the power to order the solicitor to pay compensation for distress and inconvenience, again to a maximum of £15,000, although the average payout is £450. If your loss is greater than this, you will have to take your solicitor to court. In serious cases, it can also refer your case to the Solicitors Regulatory Authority (SRA).