If the Solicitors Regulation Authority (SRA) has concerns about a firm of solicitors it will close the practice down. This is done to protect the interests of the clients and the public.
The SRA may close a firm if a member of that firm is thought to be behaving dishonestly, if a practice has been abandoned or if the firm is believed to have breached the SRA Code of Conduct or the SRA Accounts Rules.
Although the specific circumstances of the intervention remain confidential, the general statutory grounds are usually published by the SRA, which you can view on their website.