Any customer who subscribes to one of BT's consumer high-speed Internet access packages before 20 June will receive a voucher entitling them to a return economy flight to one of 11 airports in Europe and the US.
"This is yet another example of BT taking the lead in the market to drive broadband uptake and make Broadband Britain a reality," claimed Duncan Ingram, managing director of BT Openworld. "For anybody who may have been recently thinking about installing broadband in their home, now is the time."
However, BT's offer is subject to a number of conditions which have the potential to leave some customers paying more than they might expect.
For a start, the flights aren't completely free, as customers will have to pay airport tax and any travel insurance in order to get to Amsterdam, Barcelona, Brussels, Nice, Paris, Prague, Atlanta, Boston, New York, Philadelphia or Washington.
Also, customers can only depart from Heathrow, Gatwick, Stansted and Manchester. BT has warned that it's not possible to reach all 11 destinations directly from each of these four UK airports, and that customers will have pay to get themselves to the departure lounge (apart for Northern Ireland residents who also will get a return flight from Belfast to a mainland UK airport).
Voucher-holders will only be eligible to travel with "selected airlines" -- which BT says "may include BMI, British Airways, Air France, KLM and easyJet".
Once a customer has signed up, they need to give BT at least 45 days' warning of the day on which they want to travel. And finally, flights to the US airports can also not be taken during July or August.
Despite these restrictions, BT's offer could stimulate higher broadband take-up in the UK. Several rival ISPs have recently announced cheaper products, so customers will have to decide whether to plump for a subsidised flight rather than another ADSL product that might be a few pounds a month cheaper.
BT must also avoid repeating the experience of Hoover, which in the early 1990s ran a promotion where anyone who spent more than £100 on a Hoover product got a free flight to America. This offer was hugely popular -- as flights to the US at that time cost much more than £100. But the promotion proved a disaster, as Hoover hasn't anticipated the level of demand, and resulted in legal action from customers who accused the company of invoking bogus technicalities to avoid paying for their flights.