In the House of Commons statements take place after Oral Questions and usually relate to matters of policy or government actions and may be made by a minister. However, ministers may also make written statements.
A Business Statement announces the future business of the Commons and usually takes place on Thursdays. Other statements are occasionally made by an MP who has resigned or may have offended the House and wishes to explaining the reasons for their actions but this can only be made with permission of the Speaker.
In the House of Lords a Member can make a short personal statement in order to correct information given in a speech by them or to reply to claims made about them in the House. Statements by ministers on matters of public importance may be made and are usually announced at the same time in both Houses.
Further information on this subject can be found from the following link.
About Parliament: Ministerial Statements