Euros at Heathrow

Both at both. But, the only ones I saw at Heathrow a couple of months ago are the dreaded Travelex deals which rip you off on the exchange rate. I wouldn't get more than just enough to get you moving. My knowledge of St Pancras is second-hand, but I trust the source. And that source wouldn't go near Travelex if she could help it.

Well I've only gotten pounds out of the ATM at Heathrow (sometimes you have to try a second machine during heavy arrival times as a particular machine may be out of cash - rare). Presume you are taking the EuroStar at St. Pancras. After you clear security there are 2, maybe 4 (I forget) ATM machines on the far side opposite the security lines. One for getting EURO's and one for British Pounds. Also, once you arrive across the channel the regular ATM machines will dispense EUROs. Let not your heart be troubled on this matter:)

The standard bank ATMs in most countries only dispense local currency. The currency exchange machines will dispense a variety but with some stiff fees. In Ireland I did see a choice of Irish or British pounds but that was a few years ago.

I've only noticed the Euro or GBP machines in the Eurostar waiting area past passport control. I would only get enough to get by until you find a bank in country. I don't trust the exchange rates.

I would try to use a credit card for the short time in the station or airport, and avoid the issue altogether, if you are quickly going to a Euro country. Ross in Denver