Another thread on ToucanSurf here reveals that the number is 0871 511 6001.

This page on the Toucan site says that from 1 February 2006 it will change to a premium rate number costing 30p/min at all times. 

Just because they have changed their non-geographic number, doesn't mean that they have changed the underlying geographic number. Try the existing geographic (020 7549 6000) and let us know if that still works.

I've used Toucan for telephony for a few years and they have been OK. I wouldn't consider them as an ISP nor would I trust them with line rental. They definitely belong int he saynoto 0870 hall of shame for changing to 0871. They say it's "only" 5p/min when called from a Toucan customer

Toucan has changed hands a couple of times too. It was part of IDT (whoever they are), then got bought by Pipex and finally by Tiscali. The latter move is a very good reason to avoid them as an ISP

You can still use one of the 0800 number,s up until the 30/1/2008.

See: http://www.toucan.com/about/contact/default.aspx

"Toucan is changing its Customer Service telephone numbers from the 31st of January 2008.
For general enquiries please call 0871 221 2210*. For Broadband Technical Support please call 0871 423 1111*.
If you are considering cancellation or looking to leave Toucan then please call our Services team on 0871222 6399*.
Further information in relation to these changes is available at www.toucan.com.
*Calls charged at 5p/min from a Toucan phone number or 10p/min from a BT line. Calls from mobile phones and other providers may vary. "

The parent company Tiscali has already switched from 0870 to using 0871  for customer service ,and they  use  0845 for cancellations which they claim is a local call.

See: http://www.tiscali.co.uk/aboutus/contact/contact-details.html

I've been with BT for a year now and have been pretty good. If you want the infamous Indian call center, ring one of the 0800xxx numbers listed, they will tell you to ring one of the 084xxx numbers. Just say 'I have tried that and can't get through',  they then transfer you. In a year I have only contacted them a couple of times and that was at the beginning when I set the BB up. I know they are not the cheapest but  they have given me no problems.....so far!!!!!

I started a thread here about leaving Toucan.
http://www.saynoto0870.com/cgi-bin/forum/YaBB.cgi?num=1233740669

Since they are now part of Tiscali I would suggest avoiding them like the plague. Their phone offering is now worse than many and their broadband product was never really worth having.