On Tue, 8 Sep 2009 21:23:55 -0700 (PDT), tony wrote:

Last summer I bought 2 stainless steel watering cans from Tesco.
At the start of the season this year, they were showing signs of rust
and leaking.

Do they have "stainless steel" and "tesco" marked on them anywhere?
Sticky label with the barcode on the bottom maybe?

As they are rusting they patently aren't stainless steel, point this
out to the store duty manager and if you have no joy draw your local
Trading Standards into the discussion under the Trades Description
Act.

A stainless steel watering can should out last your grandchildren...

--
Cheers
Dave.