BritRail

Before you purchase the pass, make sure you have priced the single trips. Rail passes, in general, are becoming less and less cost effective when advance purchase discount tickets are available. Rail passes provide a level of convenience but you pay for that convenience. And no to your question.

we were wondering if we can use it on the trains in London that go between local city destinations too

If you can give an example of the train journeys you have in mind then you will get an accurate answer

as said, you pay through the nose for Britrail

I would carefully study the Britrail online site. They have many versions of passes available. You will need to have your itinerary in mind before your purchase. I would agree that you should check the prices of "day return tickets", senior rates?, etc. before making your investment.

If you go to the National Rail site http://www.nationalrail.co.uk and choose a random date in the future for 2 people traveling together from London to let's say, York and choose More Options and select from the drop down menu Two Together Railcard (for £30 payable at the train station in London with 2 passport sized photos) you can see fares for as little as £16 for 2 people. Can the Britrail Pass compete with that price? The £30 Railcard gives you 1/3 off on most train travel, routes and times (read the restrictions) and is good for one year.

It's all about knowing your routes, dates, flexibility and doing the math to know what is best for you.

If you are planning a rail based-holiday - up and down the country first class more or less every day etc then the Britrail passes can be a real bargain compared with what residents can get. For doing a few short or middling trips it will be poor value.

Before you buy a Brittail pass, I would be very careful to do the math to make sure you will save money versus buying tickets individually. Be sure to take into account that some routes are discounted in advance (usually 12 weeks or so, I think) and you may also find a Two Together or Friends and Family (you don't say how many "we" are or your ages) railcard will give you discounts as well.

There is good information about train travel on the website of the Man in Seat 61. There's also a train travel forum over on TripAdvisor that may be able to advise as well.

To answer the original question, I'm pretty sure the pass could be used on National Rail services within the London area - for example to places like Hampton Court, Richmond or Greenwich which have National Rail stations.

I believe that is correct---pass is good on National Rail services originating at London train stations---- but if it would be a poor value to use up a day on the pass for a £9 journey to Richmond or other close location.

It should also be valid on the Overground - which is under National Rail conditions even if they are dressed up as TfL

You can use it on all National Rail Services including London Overground and all National Rail Services in the London area.

As always, the man in seat 61 offers knowledgeable advice. http://www.seat61.com/UK-train-travel.htm#Rail_Rovers Scroll through to find the BritRail item.