We're a family of five staying a week in London in early August. Kids are 15, 13, 10. Our flat is Clerkenwell, post code is London wc1x 9qr. We will be flying into Heathrow.

We will probably tour London mostly, heading out of town for daytrips perhaps twice. We won't museum hop, necessarily. Tower of London, British Museum, you know, the usual. I assume we'll be using the Tube for most things.

Can anyone advise the best travel card to purchase and best way to buy it?

Here is why I think you shouldn't necessarily use the Tube for most things: fodors.com/forums/threadselect.jsp?tid=35013771

Think about acquiring 7-day Bus Passes for the adults when you get to Heathrow. Kids fly free, and there are no zone or peak period restrictions. You can even ride the bus from Heathrow to town. Here are a few buses that serve Clerkenwell: http://www.tfl.gov.uk/tfl/gettingaro...well-12927.pdf

There is some strategy that will allow you to use Tube travel the most economically, but there are many variations to consider: www.tfl.gov.uk/tickets/faresandtickets/1063.aspx

If you EVER plan to use the Tube, buy your bus passes loaded on Oyster Cards. Otherwise, you will have to pay exorbitant cash fares for the train rides.

10 year old travels free on all London transport, the 13 & 15 yr old's can buy a pass that costs £1 per day.

Given where you are (Percy Street?) Tube travel doesn't work as you have a bit of a walk to get anywhere BUT if you are visiting the likes of the Tower of London a Travelcard is very useful as it entitles you to 2-for-1 entry for adults for a number of places - www.2for1entry.co.uk

I'd just pay the £22 and get a 7 day Zone 1-2 travelcard. Nothing to stop you just using it on buses. Add a few quid onto it for trips - eg to/from airport - outside those zones

I think we're supposedly 10 min away from King's Cross, if the honor is being honest about things.

What is the bus ride from Heathrow to Clerkenwell like? We're arriving at 10:00 a.m. and will be dog tired, I'd guess.

AlanRow, I don't understand the 2for1 thing. The site seems to want me to log on or do a search or something. Can you advise?

You've got to register first - www.2for1entry.co.uk/Register.aspx - choose "other" for county and pick a random station

It's a 10-15 minute walk from KX but going to KX may not be the fastest way to get to places

Have a play with the journeyplanner on www.tfl.gov.uk

"What is the bus ride from Heathrow to Clerkenwell like?"

It takes 50-55 minutes to get from Heathrow to Victoria Coach Station at mid-morning (032, 412, 413, or 500 bus).

Then you take a short walk to Victoria.

From Victoria to Clerkenwell takes 45 minutes on the 38 - about the same time as the Tube with two changes.

If you put your postcode into www.streetmap.co.uk you'll get a map. That is indeed Percy Street, which is about halfway between Kings Cross and Angel tube stations.

The tube goes direct to Kings Cross from Heathrow without changing in about 50-55 minutes. From there, it's about 10-15 minutes walk, or a couple of stops on one of the half-dozen or so bus routes going up Pentonville Road:
http://www.tfl.gov.uk/tfl/gettingaro...cross-2150.pdf.

But it might make sense on arrival to get a taxi from Kings Cross, even though it would only be a short trip.

We were in London with 2 teenagers several years ago and bought the passes for all of us. For some reason the youngest son needed a photo while the rest of us did not. I brought the strip of extra passport photos but couldnt finnd them when I got the pass. Had to go to a small shop and have a new one made - probably 7 E or so. So put them in your wallet and save a few bucks. Loved the passes.

Teenagers aged around 16-19 perhaps?