We recently returned from a trip to London. My girlfriend really loved
the Ham/Cheese/Pickle sandwich from the local Sainsbury stores. The
pickle has a very distinctive taste. We originally thought it might be
using "branston pickles", but we bought a jar, and it doesn't have the
same taste.

Anybody able to provide the exact type/brand of pickle (relish) used?
It would be great if you could also provide a location of where this
can be purchased online from the United States

Perhaps one of these is the right pickle?

http://www.sainsburystoyou.com/webconnect/frameset/navigation_frame.jsp

The only way you (or a researcher) will be able to find the answer to
this is to ask Sainsbury's themselves, and they will have to ask their
sandwich supplier.  You would probably want to tell them which store
and roughly what date.

http://sainsburys.co.uk/contactus/contactus.htm

Sorry, I didn't realize the site I posted was in frames.
Here is the pickle page!   :-)

http://www.sainsburystoyou.com/webconnect/search/search_results.jsp?bmUID=1128199078035

I'd write and ask which pickle was used. Surely it's one of these!

Regards, Crabcakes

Thanks for everybody's comments. 

Before I posted my google question, 
1) I had already found the pickles page on the Sainsbury to go site.
However, there are too many different type of pickles listed. Since
I'm in the US, I didn't want to purchase every type of pickle and
wasn't sure if I could even have it shipped to the US.

2) I contacted Sainsbury via email and never heard back. 

That's when I turned to Google Answers.  I'm still hoping somebody can
point to me the exact brand/label.

I think the pickle is regular "Ploughman's pickle" - comes like a
relish in a jar and is made by Heinz.  I have not found it in US
markets.  However if you google "ploughmans pickle" you'll find a
variety of on-line stores that carry this and other British products
and ship directly to you from UK.