I wouldn't put any of my card details in an email - you can never be sure where the email might end up.

We had to pay a deposit with a hotel in Malta for next January and they requested the card details by email. I phoned them instead which I felt was safer - they did seem a little suprised that I was reluctant to supply the details by email though.

I would phone the hotel instead - it shouldn't cost much and you will probably feel happier having spoken to someone anyway.

Pippa

Fax or Phone only emails aren't encrypted

I've got enough trouble with people getting access to emails I've sent - I'd never put card details in one! Just remember that if you've got a computer connected to a phone line there's a good chance you can fax a message from it. "Print To Fax" drivers are often loaded as standard, you just have to select under printers - if it isn't there look in the Add Printers bit and see if it's waiting to be added. Then all you have to do is create your message in Word or Notepad etc.. and "print" it, select fax instead of your actual printer. I've done this quite a few times with hotels, if they send an email asking for details I send a reply saying check the fax machine in order to keep the email thread intact in cas ethey say I didn't respond.

Thanks for the replies.
I have emailed the hotel saying we would like to upgrade and will either pay when we arrive or can supply card details by phone or fax. Will have to wait and see what they say.