bedelman- the Premium First lounge is normally only available to those travelling Premium First (Eurostar has three classes: Economy, First, Premium First). However, if you have a (UK?) Amex Platinum or Centurion, you can get acess independent of ticket held. Even a student ticket.
In fact, I did just that last October- I bought a under-25 ticket for myself and partner (i.e. ultra-cheap) and on arrival went to the Premium First lounge, showed my Amex (at that time Platinum) and they showed me the way in... after a little flirting they let my partner in too although as said officially its cardholder only. Same worked at Waterloo.
Its the same access deal as the Virgin Clubhouse / BM Diamond lounge and is documented in the associated card Travel Packs.
dnw
[This message has been edited by dnw (edited 07-04-2001).]