Necktie Mike pinched from mum's bed (5)
I believe the answer is:
ascot
'necktie' is the definition.
(I've seen this before)
'mike pinched from mum's bed' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'pinched from' suggests deleting specific letters.
'mum's' becomes 'ma's' (ma can mean mother).
'bed' becomes 'cot' (cot is a type of bed).
'mas' with 'm' taken out is 'as'.
'as'+'cot'='ASCOT'
(Other definitions for ascot that I've seen before include "sporting venue" , "Famous racecourse" , "Royal race course" , "where some of our betters may be" , "Berkshire race course" .)