Finance Act 2003 Schedule 7 has the answer
Many Properties Transactions within Groups of Companies are Exempt from SDLT
Stamp duty land tax: group relief and reconstruction and acquisition reliefs
1(1)A transaction is exempt from charge if the vendor and purchaser are companies that at the effective date of the transaction are members of the same group.
(2)For the purposes of group relief—
(a)“company” means a body corporate, and
(b)companies are members of the same group if one is the 75% subsidiary of the other or both are 75% subsidiaries of a third company.
(3)For the purposes of group relief a company (“company A”) is the 75% subsidiary of another company (“company B”) if company B—
(a)is beneficial owner of not less than 75% of the ordinary share capital of company A,
(b)is beneficially entitled to not less than 75% of any profits available for distribution to equity holders of company A, and
(c)would be beneficially entitled to not less than 75% of any assets of company A available for distribution to its equity holders on a winding-up.