A Northampton off-licence has been called in for review after a worker allegedly struck a customer over the head with a "length of wood".
The owners of Nene Valley Stores could face a series of conditions placed on their licence following the suspected incident earlier this year.
An official submission to Northampton Borough Council by licensing police states that, on October 19 this year, a customer was refused service and struck with a wooden baton after getting into an argument with a shopkeeper.
When officers arrived at the store they also discovered the worker was a suspected illegal immigrant.
The police submission by PS Martin O'Connell goes on to say: "There appears to be no reason why, after what looks like a refused sale to two customers by the shop worker, potentially for good reason, that they were followed out of the store by the shop worker.
"This is a clear case of excessive force being used."
The police objection states that, at about 6.30pm on the evening of October 19, two men entered the shop in St Andrews Road and asked to buy alcohol.
The shopworker and customer became involved in an "altercation", which carried continue outside.
The employee then went back into the store and reached for a hammer before returning outside, CCTV images show.
Shortly afterwards the shopkeeper can be seen going behind the counter again, the police submission states, to exchange the hammer for a wooden baton.
He then allegedly went outside again to strike the customer.
Northamptonshire Police will argue that the that the shop licence is amended by four new conditions during a hearing at the Guildhall next week.
Among them, officers say the store owners should carry out more rigorous employment checks and implements such as "hammers, knives or wooden sticks or bats" should not be kept behind the tills.
Two people must be working in the shop at any given time after 6pm, police say, and staff involved in the sale of alcohol will also need to undergo yearly training sessions.
The licencing hearing will take place on Monday, January 8, at the Guildhall main chamber at 10am.