Can I take data of clients with me when I change firm?
When you change or leave the employ of one firm you are not permitted to take clients’ information/data with you. A client’s contract is domiciled with the firm, not with the person handling their matter. The data i.e. contact details and any information about their affairs naturally belongs to the firm and should you remove it from the firm you will be breaching client confidentiality. This also includes data belonging to former clients of the firm as well.
You should neither approach old clients asking them to leave the care of your current firm or take (without permission) instructions to your new firm. It may be acceptable to contact clients before you leave explaining that you will be leaving and providing them with the details of the nominated person who will be handling their matter, all though it is likely your existing employer will have procedures in place for this situation.
In such circumstances, you should have regard to an ethical code of conduct, which suggests that you must not engage in any conduct that may or could undermine or affect adversely the confidence and trust placed in you by your existing employer.
This all explained of course, clients are free to instruct whoever they choose to carry out their legal affairs and because of your departing they may elect to stick with you, change firms and move with you. That explained, you must not make any approach to encourage them to do so.