some one told me that 'Lets' word does not exist in the british english, is this true? if no, Kindly explain in what context it is use if you can throw a little light on this
It's probably true that British children say "let's" more often than British adults. This may be because "Let's do X" implies a keen or enthusiastic desire to do X, on the speaker's part; and most British adults do most things only with reluctance.