I have 1 week

I would stick to England as Scotland really deserves its' own 2 week trip. My sister and I did this a few years ago with 1 week in London and the other in Bath, Conwy, Keswick and York. I recommend if you can doing the out and about week first and then London as your second week. That way you are already there for the flight home. We did it that way and it worked great. Train to Bath, car to Conwy, Keswick and York. Then we dropped the car in York and trained it to London.

It's really hard to say because so much depends on your interests and priorities. If you want to get a taste of Scotland for your second week, you could take the train to Edinburgh, then fly home from there (or Glasgow) at the end of your Scotland week. OTOH, there are limitless wonderful things to see and do in England, not to mention Wales.

Completely agree with JLKelman

Have you already bought flights? If you have, and they are round trip in and out of London, stick to England; it makes the logistics much easier. If you can buy flights into London and out of Glasgow or Edinburgh, seeing a bit of Scotland on your second week can work. But note that it's only going to be a bit, and you still lose a fair amount of time getting from southern England to Scotland.

Yes, stay with England. Here's a rough outline for a trip N of London-- York, Lake District, Bath, Cotswolds. You can fill in the rest.

Driving tip: Never eat lunch between noon & 2:00pm. That's when everybody eats & traffic volume drops. Hit the road during lunch hour.

Learn about the National Trust, which owns more that 10% of the UK and just about everything a tourist wants to see. We never went driving in the UK without the National Trust map, about 200 pages, which shows about 75 places to visit on every page.

They used to have an absurdly cheap all properties admission pass for foreign tourists. Don't know if they still do, but it was one of the great bargains in travel.

Come back and see Scotland on another trip. You can's see much of any country in two weeks. We spent four weeks in Wales and England and didn't go to London or Scotland. We still didn't see everything we wanted.

You can take in cities like Cambridge, Canterbury, Oxford, Blenheim Palace, Windsor Castle, Salisbury, Stonehenge and the Cotswolds on day trips from London.

What are your interests? Stick to England if your flight home is from London.

In July, Bath, Conwy, the Lake District, York and back to London sounds like travel pergatory all in one week. It sounds as though you maybe prepared to rent a car?

You could pick one area and explore it well, such as south east England where you could explore castles - Leeds, Dover, Hever, Arundel or Bodiam. Historical towns such as Canterbury, Chichester, Winchester, Lewes and Rye. Many gardens and historic houses.

Alternatively, visit north Wales for castles, Llangollen area for traditional horse pulled canal barge rides, Snowdonia for mountains and nearby historic Chester. Liverpool is also an easy day trip.

I'd also suggest it depends upon your financial situation. If you can swing England this year and Scotland the next, then I'd go that route.

If this is your one big trip to the UK, then yes, maybe see some of both countries. Obviously this would be a "highlights" sort of trip.

Thanks for the posts everybody. I have no choice but to be in London in the first week because of a wedding. But other than that I am flexible. With two kids in two I think the posters here have convinced me to stick to England. I think I am going to drive to Wales, then go a little south and work my way back to London for flight home.

My son is a big soccer guy so maybe we can stop by in all the cities he has only heard on TV, like Swansea etc.

I will be back to collect some feedback on a 1 week trip to England.

Be sure to go to St. Fagan's Welsh Life Park near Cardiff. Wales is underrated compared to the more visited sites such as Bath and Cotswolds-I preferred Southern Wales to both of those destinations, mainly because I enjoyed St. Fagan's so much.

I have no choice but to be in London in the first week because of a wedding

But surely the wedding is only one day ; )

My wife and I have been to Bath on two occasions and love it. There is much to see there and a free walking tour every day. We also enjoyed Salisbury and the Cathedral. If anyone in your family has any interest in ships or British history and you want to go to Portsmith, the historic Naval shipyard is amazing and the HMS Victory alone is worth the price of admission with the free audio guide that will keep everyone interested. You could easily spend an entire day at the ship yard, (again, if you like ships).

My 2 cents.......
SO much to do and see in England. It's my favorite country.
It's all really accessible too. Just drive! Find a town or city, have lunch or dinner there, and just enjoy it all.
We never EVER have an itinerary, other than today we are going to London, or Today we are going to Bath.
We don't decide that all until we are eating breakfast on the same day. I have never had a bad day there. It all comes together for some reason and always works out.