Update, 5 November, 3pm. The Scottish Power tariff mentioned in this article has now gone but British Gas Fix & Fall is just as expensive so it's still worth looking elsewhere. See the Cheap Gas & Electricity guide for the top deals.

MoneySavingExpert.com is today warning people not to be seduced into signing up to the flagship British Gas Fix & Fall tariff. Here's the view from founder Martin Lewis.

British Gas is jumping on the bandwagon that people should fix now, but that is about fixing cheaply and this tariff is not cheap.

This heavily-pumped deal's big sell in its widespread TV and radio ads is you can guarantee no rate rises for two winters, with the bonus that if prices fall, so will the cost of your deal.

It's a clever concept. Indeed, I've been swamped with questions and tweets over whether this is worth moving to.

Yet while the idea's good, and everyone should currently be considering whether fixing is right for them, it's vastly overpriced compared to the best fixes on the market.

The cheapest fixed rate deal that lasts a similar time is from Scottish Power*. Someone with typical bills pays an average £170 a year less with it than with British Gas Fix & Fall.

Important - which tariff is cheapest for you depends on where you live and usage. Use a comparison site such as Energyhelpline* (which gives £15 cashback per switch via this link) or MoneySupermarket* (which gives £30 dual fuel cashback) to see which is cheaper. Full info: Cheap Gas & Electricity.

Plus the Scottish Power tariff has no early exit penalties, so if prices did drop so substantially that you needed to move, you wouldn't be locked in.

Not only that, the chance of the 13% drop necessary to make British Gas cheaper than Scottish Power would be the biggest-ever price fall since privatisation, and is therefore unlikely. Even then, you would have been paying more in the interim, so would only save if that price fall happened soon.

If you've recently switched to the British Gas tariff, I'd suggest you check out whether you're still within the cooling off period and can shift to a better deal.

Yet don't let this put you off acting and getting your bills sorted. There are big savings to be had compared to standard tariffs.

The figures below show how British Gas Fix & Fall stacks up against the competition in each energy region.

British Gas Fix & Fall's average annual price compared
Region British Gas Fix & Fall Cheapest fix, no exit fee (Scottish Power) Cheapest fix with exit fee (Ovo), though it's a shorter fix
Eastern £1,299 £1,124 £1,117
East Midlands £1,282 £1,121 £1,118
London £1,314 £1,147 £1,138
Manweb (Liverpool) £1,329 £1,176 £1,160
Midlands £1,329 £1,128 £1,136
Northern £1,295 £1,125 £1,124
Norweb (Manchester) £1,298 £1,130 £1,139
Scottish Hydro (Aberdeen) £1,302 £1,163 £1,110
Scottish Power (Edinburgh) £1,290 £1,135 £1,138
Seeboard (Brighton) £1,320 £1,129 £1,166
Southern £1,323 £1,143 £1,160
Swalec (Cardiff) £1,319 £1,164 £1,196
Sweb (Bristol) £1,339 £1,164 £1,108
Yorkshire £1,284 £1,111 £1,139
Nationwide average £1,309 £1,140 £1,139
Source: Energyhelpline.com