Postcodes in the UK are composed of two groups of letters and numbers, separated by a space.
The first group starts with a one- or two-letter prefix, followed by a one- or two-digit number, or one digit and a letter.
The second group is always one digit and two letters.
Examples:
A postcode typically covers a business, a P.O. box or group of boxes, or a portion of a residential street.
2010
67450
+971
88100, 56100, or alike
83700
The postcode of hyderabad starts with 5000XX
What is the postalcode for Nanyuke, Kenya
chapionship
postal cood of landhi Karachi is 75160
21100 is the postal code of India in yahoo
There is no such number in the UK.
As far as I know, it is not an UK number.