I should like to congratulate the hon. Member for Brentford and Chiswick (Mr. Barnes) on his success in gaining time for tonight's debate. I welcome the opportunity to emphasise, as I have done before, how conscious we are in the Department of the need to smooth the flow of traffic from the M3 into London. I am also grateful to my hon. Friend the Member for Twickenham (Mr. Jessel) for joining in this debate and re-emphasising some of the important points which he raised in the debate he initiated in July.

My hon. Friend made it clear on that occasion that a great deal had already been done and planned for the time that the M3 opened as far as Sunbury, but the subject of tonight's debate is of special interest not only to the hon. Member for Brentford and Chiswick and my hon. Friend but to other hon. Members for neighbouring constituencies. I hope that I can give all concerned some further reassurance. My hon. Friend the Member for Heston and Isleworth (Mr. Hayhoe) has been in correspondence and conversation with me on more than one occasion to let me know the very strong feeling which exists among those living near the A316. He tells me that an increased flow of traffic would be much resented by the local community, and he left me in no doubt about this and their deep-rooted feelings about this matter. I appreciate that very much.

The Greater London Council, of course, is the highway authority for both the A316 and the A305. I know that hon. Members will understand if I have to say that this area is a matter for the council. Local govenment being what it is, it would not be right for me to try to tell it what to do with its roads. But I can assure the hon. Members that the suggestions made tonight, like those which my hon. Friend made in July, will be drawn to the attention of the GLC.

The extension of the M3 to Sunbury is due for completion next May. At the same time the GLC is expected to complete improvements to nearly two miles of the A305 which links the M3 with the A316 at the Hope and Anchor roundabout. The A305 will initially be to dual two-lane standard, becoming probably in the autumn of 1975, a dual three-lane all-purpose road.

The GLC appreciated the possible effect on the A316 and on routes crossing it. The council accordingly asked that the preparation list of metropolitan road schemes be adjusted to include schemes to improve the A316 roundabout junctions where congestion occurs at peak times and to provide improved facilities for pedestrians crossing the route.

My right hon. and learned Friend the Secretary of State will consider these schemes for grant, and I understand that the GLC is considering the proposals with the London boroughs affected. As far as the Department of the Environment is concerned, in these schemes there will be no unnecessary delays. The adjusted preparation list was publicly announced of 18th September. The GLC intends to complete the schemes as quickly as it can.

Other traffic management schemes are being implemented before the M3 extension is opened. Their purpose is to reduce the impact of the additional traffic. The measures were the result of recommendations made earlier this year by a working party consisting of representatives of my Department, the GLC, Surrey County Council, the London borough of Hounslow and Staines Urban District Council. Among such measures are the improvement of the roundabout at Feltham Hill Road and the provision of direction signs on the M3 to encourage North London, Heathrow and M1 traffic to use the A30.

Additionally, as the hon. Member and my hon. Friend mentioned, the proposed tapering of the M3 from three lanes to two lanes west of Sunbury Cross will continue only as long as necessary. My hon. Friend even asked me to consider tapering to one lane. I cannot give such assurances tonight. However, the whole situation at the end of the M3 will be examined on the completion of each stage of the A305 and A316 roadworks. I cannot go further than that now.

As to the possibility of the A316 becoming a motorway, the report of the panel of inquiry into the Greater London Development Plan, under the chairmanship of Mr. Frank Layfield, QC, was published earlier this year. In it the panel proposed that a new major route be provided to relieve the northern end of the A316. This route would remain south of the river and join the A3. My right hon. and learned Friend is considering the plan and the panel's proposals. Meanwhile, the A316 will continue to be the most likely route from the M3 for traffic travelling to or from central London.

My right hon. and learned Friend has no plan to upgrade the A316 to motorway standards. I have given that assurance before. Any such suggestion could come only from the GLC, whose responsibility the road is. I am not aware of any such proposal from the GLC. My Department has no such proposal; it is not even for us to propose. In fact, I understand that the present council is proposing to eliminate urban motorways from its plans entirely.

There are about eight miles of A305 and A316 between Sunbury Cross and the Hogarth roundabout which will themselves act as a traffic filter. I know that the GLC will be keeping under continuous review the effects of the improvements to these roads, with the object of taking any further measures that may prove necessary.

The hon. Gentleman raised the matter of the installation of linked traffic signals, which seemed to be questioned by my hon. Friend. The hon. Gentleman also raised the question of the designation of the A316 as a clearway and made a very strong plea that the A316 should not become a designated lorry route. I understand his fears and problems on the clearway and the designated lorry route. All these matters, including linked traffic lights, are best directed to the GLC, whose responsibility they are.

Roadworks will be continuing along the A305 until at least the autumn of 1975. These will act as a throttle on traffic between the M3 and Chiswick.

The hon. Gentleman should put his suggestions for specific traffic management schemes to the GLC. If it brings forward schemes we will consider them and evaluate them in co-operation with the GLC and, if there is agreement, they may qualify for appropriate grant. But it must be a matter for the GLC in the first place.

The Hogarth flyover is not the critical factor in causing congestion at the Hogarth junction. The limit is the capacity of the roundabout itself. Unless further works are carried out on the A4 east of the roundabout as far as Hammersmith, further improvements to Hogarth roundabout will have minimal effect.

The Department will be adding temporary directions to existing signs on the outward-bound lane of the A4 approaching the Hogarth roundabout to direct M3 traffic along the A4 and the A30 rather than along the A316 to the M3. The GLC is considering in detail the problems of signpostir from London to the M3, with the intention of implementing its proposals before the M3 extension opens.

Many of the questions which the hon. Gentleman has put to me, which rightly concern his constituents, are properly matters for the GLC. I assure the hon. Gentleman that both the council and my Department have taken fully on board the possible difficulties caused by the opening of the M3 extension. But I believe that the remedial measures largely proposed by the GLC, with which we are co-operating, will go a long way towards solving the problems.

Of course, in many cases we do not know exactly how the problems will turn out, as I made clear in the debate in July. Everything said in tonight's debate will be brought to the attention of the GLC and we will examine it in the Department. We and the GLC, in co-operation with other local authorities concerned, will keep a close watch on what is happening and what happens after the M3 is opened.

I assure the hon. Gentleman that my Department will not unnecessarily delay any procedures or proposals put by the GLC to us. In a difficult situation for all the constituencies in the western part of London, they can rest assured that my Department and the GLC will do all they can to make life as reasonable and as civilised as possible.