Hampden (SP?) and Kew Gardens can be done in a long day.

Dm
Not sure about how far in advance, but in general, the earlier the better. Don't quote me on £20 as it may be a bit more.

There are no very cheap day returns to York you can buy on or near the day.

There are a limited number of tickets you can buy 7 days or more in advance, stargting at £30.

Availability of these may be limited on peak trains - which, by definition, tend to be northbound trains leaving earlyish and southbound trains leaving late afternoon-early evening - in other words, the trains you need for a day trip.

They may be be gone well before the 7 day deadline. Buy them now.

While in London last year I took many day trips. Bath and Stonhenge, and the Burton-on-the Water in the Cotswolds being my favorites. There is a tour company that I used called Evan Evans. I was very happy with them. The Cotswold stops I experienced were lovely, and i also was able to check out a couple of beautiful churches. My favorite thing besides castles while in England and Scotland.

You've got to see Windsor Castle and it's not too far outside London.The town of Windsor has some lovely shops and restaurants too.It's a must in my opinion.

I vote for Bath or Cambridge. Bath is a great overnight trip, but as a day trip it is doable. Cambridge is not too far and is one of the greatest college towns in the world.

Did you mention what time of year you will be there? In spring and summer, one of our favorite day trips is Kew Gardens.

do something entirely diffent, take the train to southend on sea, about
45 mins from london, is londons seaside playground, a great day can be had, plenty of winkles and fish to eat and plenty of good pubs .