I've noticed that many other sites also sell Durex condoms, and much
cheaper than in shops. Eg.

http://www.britishcondoms.com/durex-condoms/?gclid=CK6Cl6fu0IYCFTQYQgodIzj08g

and 

http://www.condomcare.co.uk/

Does Durex endorse these products, i.e. are they genuine - and can they be trusted?

Thanks

martismo

They are probably second hand

Kemlo

I have had a friend who uses these condoms from websites (one website
was selling them so cheaply he bought 1000 and gave them away) he had
NO problems. Ensure that if you want to order off these companies that
you make a small order first and try them out before making big
purchases.

Alternatively, your family planning clinic give away FREE
contraception to all those that ask.

You cannot get cheaper than that :)

Usrhlp

But they never have the extra large.

*sigh*

No specific information but both companies and SSL International were
mentioned in this Office of Fair Trading Report on the condom market
in the UK.
Condoms - Review of the undertakings given by LRC Products Limited 
http://www.oft.gov.uk/NR/rdonlyres/6A828CA0-E28D-4336-BD20-331D45D0A179/0/oft837.pdf

Thanks for the comments, I've also written to Durex and they explained:

"Durex supply to wholesalers who then supply to different stores and
internet websites.

Without having any batch details of the condoms  we are unable to
guarantee the authenticity of them.

All Durex condoms are manufactured in either India, Spain or Thailand."

In response I have sent details from the back of a condom bag of a
previous purchase from CondomCare. I did not experience any
difficulties with the previous bunch, but started to wonder why they
are able to sell it so cheaply when getting it straight from Durex has
no obvious advantage. This made me suspicious.

But at the moment it looks reasonable, although I still don't know why
it makes business sense.

I received the following reply back from Durex, which pretty much
answers my question:

"Thank you for your e-mail message regarding Durex.

The manufacturing site have come back to me and have confirmed that
the Durex Extra Safe Condoms that you have bought are genuine Durex.

If you have any more queries please feel free to contact me.

Thank you once again for taking the time to contact us."

Durex was quite responsive and helpful.