It's called Olympic beach volleyball.

It's essentially happening at the spot of the Horse Guards Parade.

If you've seen any of the sport, you will see that you couldn't tell where it is.

No, the park is not a "goner".

Some of the park is taken over for the beach volleyball but the area by Buckingham palace should be the same as always. Everything is not dirt or mud. Depending when you come in sept they might still be using the venue for the Paralympics so you may not have access to the end by horseguards and it sounds like that part may be impacted until next year.

Do you mean you would cancel your visit to London if this park is not available? Or just your hotel? There are other nice parks in London...try regents park...

Till the end of the Paralympics (mid-Sept) access to the NE quadrant of St James' Park will be virtually impossible or at any rate restricted. From the end of the mainstream Olympics, access to the rest of the park will be more or less unrestricted, except on the day (and possibly a day or so just before and after) the Paralympic Marathon (September 9, and almost certain to attract crowds around the Mall and St James' Park on a scale no disabled athletic event in history, anywhere, has even approached)

From mid-Sep, access around the park will be unpredictably restricted, though mostly (apart from the NE quadrant) trivially, as the area gets reinstated. No-one will have the faintest idea what needs reinstating in the NE quadrant till the stuff erected has been fully dismantled and the ground's been examined.

There's next to no significant damage in the "other" three quadrants: the work over the following six months is mostly dismantling food stalls and the like. Nature being what it is, the ducks and squirrels won't care, so the non-human fauna's likely to be completely unaffected. But the work of reinstatement might make the area a tad industrial-feeling from time, so humans might prefer to hang round another bit of London parkland (there's no shortage, though the damage from the summer junketings to a lot of Hyde Park's grassland is almost certain to be greater than to even the NE of St James Park).

Park administrators being what they are, though, I'd expect far more fundamental basic gardening jobs (heavy remulching, reseeding etc) to be chucked in than usual during the late summer and autumn while the workmen are doing their thing. The "other" three quadrants certainly aren't goners (or even "temporarily awayers") - but they may look a bit more like my garden this winter than usual.

Daph, just curious, what else do you folks enjoy in London other than St. James Park?

Thanks for all your helpful responses! We shall study the excellent map on the London Parks site and try to figure it all out. Yes, we like the other parks and visit them on most trips to London but St. James's is far and above our favorite. Hate to see it messed up. This might be our opportunity to see more of the UK although it's difficult-husband excellent driver but not on the "wrong" side of the road. Bus/train tough on seniors who have even one medium sized rolling suitcase.
What do we do other than parks in London?
Museums, plays, walks, restaurants, shopping [not much buying]. Not to mention Changing of the Guard, to which I am addicted. London so expensive-parks are free, as are the summer band concerts- mainly cancelled this summer, from what I can tell.

Daphnis, not sure where you are getting your info from but there are far more free events all over the city, like impromptu concerts, all over the city this year...

Just one site I found with a quick google http://www.visitlondon.com/events/special/

Sorry that was supposed to be daph, but was autocorrected!

You can see a lot of the UK without driving. Smaller cities like Bath, Bristol, Oxford, York, Durham, nice towns like Salisbury, Cambridge, Brighton, Winchester, Some of these can be seen on daytrips from London as well as closer sites like Windsor, Hampton Court Palace, Richmond, Greenwich. You can even do a bit in Scotland: Edinburgh, Glasgow, St. Andrews, Stirling.

Most of these places can be done by train or bus; you can save a lot by buying your train tickets early. Another option is one-day bus tours.

But I think the driving is not all that hard. That once you -- or your husband -- tries it, it will be no problem. Caveat: we've always rented an automatic for Britain. I am fearful of opening the door when I try to change gears.

If you've only been to London, there's a lot of Britain left to see. The beautiful English countryside, especially in spring, looks like one big park. Or maybe a golf course. And outside London the pace of life is more relaxed, people will talk to you.