I mean trousers with a crease in them rather than cords or moleskins. And not chinos. Non cotton. Wool or blends.
Kingston is the second biggest shopping area in the capital apart from dedicated shopping malls like Blue Water.
I could only find trousers in Marks. Bentalls only sell suits - no trousers or sports jackets. John Lewis had one pair of navy trousers.
I regret to admit that my last two pairs did indeed come from M&S (at Bluewater I think).
I guess you could go to 'designer' stores and pay much more for lower quality (than Marks). I think it's a sign of the times - the separate 'proper' trouser is another endangered species.
In Kingston, I would try the Aquascutum and Gieves and Hawkes concessions in Bentalls. They have wool trousers and Aquascutum may have some sale stock left. G&H have some sport jackets too. Austin Reed, on the first floor of the Bentalls centre has wool trousers and sports jackets too. You will find more in John Lewis, mainly own brand.
What is the strange mystery of Closet Case, 47 Brewer Street? What murkings going on and seedy invitations to the devils own delights? I for one will not venture there, for strange curious mutations of the human form do inhabit there, iGents of the most hideous mugwump variety, all bow legged, midgets feeding on the flesh of 1920's musty old tweed.
I would try John Bray on Jermyn street: they have a lot of basic stuff, and you can get a decent deal if you can bargain.
On the other hand, you'll find much better quality at M&S on marble arch than on any other M&S (I guess that their luxury 125 years suit is probably second to none in terms of value)
Generally for quality and value for money, M&S are hard to beat. Their wool/poly blend is very good and as washable trousers are required, I would strongly suggest M&S, another advantage with the wool/poly blend, is that if you are caught out in the rain, they tend to dry quicker and retain their shape.
Well, I wear a suit about once every 10 years, so I bought a £25 one from Tesco and I'm a huge fan of Massimo Dutti, good quality classic reasonable priced stuff, the man gets some good stuff there, not sure if Benetton have a good men's selection but their women's stuff is great.
M&S are great for the price and range. Ralph Lauren also do a small number - last time I was there I noticed some great grey flannel trousers, but they're not cheap.