Surrogacy arrangements in England are not illegal (provided that they comply with the law) however surrogacy contracts and agreements are not enforceable. It is for this reason that many couples look to make arrangements in a jurisdiction where there is legal certainty and enforceability.
In England it is illegal for any person to negotiate, arrange or make surrogacy arrangement for a fee. This does not however prevent the commissioning parents and the surrogate themselves from doing so. The law is designed to deter commercial agencies.