have your hand in the till
have (one's) hand in the till
To be stealing money from one's workplace or employer. Margaret had her hand in the till for years, but she finally got caught after she claimed her two-month trip to Paris as a business expense.
have your hand in the tillor
have your fingers in the tillmainly BRITISH
If someone has their hand in the till or has their fingers in the till, they are stealing from their employer or from an organization they are involved with. Thirteen company directors were found with their hands in the till in the first quarter of this year. There are rumours that a number of officials have had their fingers in the till. Note: You can also talk about people being caught or found with their hands in the till or with their fingers in the till. He got caught with his fingers in the till once too often. Note: The usual American expression is catch someone with their hand in the cookie jar.