Public-traded companies are independent, so no merger or consolidation applies. Here is what the U.K. regulatory body defines a 'relevant merger' (regardless if U.K. or internationally-based):
the creation of a relevant merger situation as defined in section 23 of the Enterprise Act 2002 (“the Act”), in that:
(a) two or more enterprises will cease to be distinct;
(b) in the course of the enterprises ceasing to be distinct, a person or group of persons will bring a relevant enterprise (as defined in section 23A of the Act) under their ownership or control; and
(c) the value of the turnover in the United Kingdom of the enterprise being taken over exceeds £1 million.