We’re not actually that keen on bags since the railway companies got folder-friendly, but they have their uses.Yachtsfolk need to protect their bikes from salt spray and flying bowsprites, whatever they might be, and the same principle applies to those regularly checking a bike in as anonymous luggage, whether at the airport, the restaurant or even (particularly even) Mrs Hampton’s Bordello & Old Time Massage Parlour. Of course, you may think you need a bike bag for another reason; whatever, it will leave your wallet thirty quid lighter and your Brompton nearly a kilogram heavier.

The Bigfoot Bag is made in Britain, from grey, green, navy blue or red cordura. It’s a waterproof fabric, but you can expect the untaped seams and very long zip to leak under extreme conditions.The bag has carrying handles and a shoulder strap, makes a nice snug fit around a typical Brompton and will just accept a bike fitted with the extended seat pillar too.The bag also comes without branding to reduce the risk of theft. Maybe, but that’s not much use if the thief is working on the lucky dip principle.

At 910g, the Bigfoot is mid-range in the Brompton bag world – somewhere between the Brompton cover and the ‘B’ bag reviewed in A to B 44. Just for the record, the ‘B’ weighs 2.3kg and gives serious protection; the basic Brompton cover weighs 290g and gives very little protection; and the super-lightweight cover we use ourselves for libraries and the like, weighs 100g and gives no protection at all. Horses for courses.

We wouldn’t recommend buying a bag unless you’re sure you need one, but for certain applications,something of this weight could be quite useful.The downside is the 910g of extra baggage, and a packed size of about 40cm x 10cm x 10cm.

Bigfoot Brompton Bag £30 (trade enquires welcome) . Bigfoot Bikes 50 Hayes Street, Bromley, Kent BR2 7LD . tel 0208 462 5004 mail bigfootbikes@yahoo.com