GBP to yen in the UK or in Tokyo?

We are flying to Haneda in a few weeks and are trying to decide whether it would be cheaper to get our yen in the UK or in Tokyo. Do you know where we would get a better exchange rate?
Any advice would be very much appreciated.

Anywhere but an airport?! I have a shot of sell/buy rates quoted GBP at 195/167, a 15% spread. (Narita 23rd Feb)

You can exchange at the banks in Japan/Tokyo and you could get a better rate, but you'll probably do as well at home, and you'll save time messing about doing the exchange in Japan.

Historically, GBP to Yen rates are higher now than they've been for some years. If you've been visiting Japan over the last few years, you look at today's rate and think it looks really attractive.

Over the next few weeks, there's a reasonable likelihood of fluctuations (who knows whether up or down?) in GBP as we get closer to a general election, so you *might* just want to take today's rate and have certainty, rather than gamble on getting a few more yen per pound (and we're likely only to be talking about a handful of yen/pound, maybe half a percent) in a few weeks' time.

Or you do both and spread your risk: buy some now to lock into a price (which is what we've done, to cover and fix the price of hotels booked, etc), and exchange some (or use cards to withdraw some) while you're there.

Might be worth checking with your bank as to how much you will get charged for using your card abroad. I'll be using a currency card (Caxton FX)) while I'm there due to the shocking fees Natwest apply when withdrawing money or using the card for purchasing.

People here have mentioned in the past that the Pound to Yen exchange is better in the UK than in Japan.

As John says.
But if you want to compare, this is the age of the internet and you can easily see the rates online. Look at
http://www.narita-airport.or.jp/exchange_e/index.html
and then compare that with the latest rates of your own bank.
But for convenience, why not just use your ATM card? Unless your bank charges rip-off fees, you are likely to do fine that way. See:
http://www.jp-bank.japanpost.jp/en/ias/en_ias_index.html
http://www.sevenbank.co.jp/intlcard/card2.html

Very helpful link to the Narita rates. Thanks for that.

Narita rates are pretty good. You can shop around and get slightly better rates in the UK, though.

i use ACE FX postal delivery service in the UK and find their rates to be far better than most.

As stated previously, the exchange rates at the airports are atrocious. The banks give a better rate, give that a try. Also, if you have an ATM card, then see if you can use it in Japan. The ATMs at the post offices and 7-11 accept foreign ATM cards and the exchange rates are very good in spite of paying the ATM usage fee.

Good luck.