Does the UK need to follow suit and establish a national committee? No. In particular, the role of a national bioethics commission would be quite different from the role of the existing Human Fertilisation and Embryology Authority (HFEA). The HFEA is a statutory regulatory body, charged with licensing and monitoring research and clinical practice as well as policy. It is accountable to Parliament as well as being subject to the courts, and indeed is regularly made to account for its decisions in practice as well as in theory. As Quintavalle pointed out, a national bioethics committee could hardly take over the regulatory functions of the HFEA, although it could conceivably take over the policy role. Were it to do so, the policy decisions of the national committee would be no more, and possibly less, accountable than the existing HFEA, and would lack the support of explicit legal principles which bind the HFEA's decisions.
Moreover, as a single committee on bioethics, it would be responsible for the whole range of bioethical topics, from those covered by the existing Human Genetics Commission and HFEA to those relating to medical research, clinical practice, and possibly the remit of the Agriculture and Environmental Biotechnology Commission or the Animals Procedures Committee. The workload of such a committee would be unmanageable, unless, as with the Nuffield Council on Bioethics, it worked in depth on particular topics for extended periods, and would therefore lack responsivity to 'hot' topics.
Central roles of a national committee would be to advise ministers or the professions, on the one hand, and to stimulate public debate, on the other. A feature of the United Kingdom is the sheer range of different public and civic groups concerned with bioethics, and it is far from clear that a single committee would improve the quality of debate or add to existing discussions. So far as ministerial advice is concerned, ministers take advice from a variety of sources (or none!), and it is unrealistic to suppose that professional bodies (such as the British Medical Association or the Royal Colleges) or statutory regulators (such as the General Medical Council) would simply be told what their policy should be and then fall into line.
The only consequence the establishment of a national committee would have, other than jobs for the great and the good as usual (and the usual great and the usual good, in all likelihood), would be the creation of a high profile target for lobby groups and for political sniping. It certainly would not improve the quality of bioethical debate in the UK, nor would it have any substantial influence over public policy or government.