Warner Bros has banned a woman who runs a restaurant at her home in west London from hosting a Harry Potter Night to celebrate Hallowe'en.

The owner of The Underground Restaurant, who uses the pseudonym Ms Marmite Lover, regularly holds themed evenings and for her latest event she had planned a menu of food and drink enjoyed by Harry Potter and his friends in the JK Rowling stories: from dandelion wine and pumpkin soup to Dumbledore's favourite sweets, such as mint humbugs. Guests were to be taken down Diagon Alley (the side of the house) before entering and would be met by a portrait of the "Fat Lady" to whom they would have to give a password.

However, Warner Bros has written to her warning that it owns all things Harry Potter: the "name, stylised logo, the name of the characters, themes, incidents and other associated indicia from the series of... books and films".

The letter from the company's legal and business department says: "Dear Ms Marmite Lover. While we are delighted you are such a fan of the Harry Potter series, unfortunately your proposed use of the Harry Potter properties... without our consent would amount to an infringement of Warner's rights."

Ms Marmite Lover has now renamed the event, as Warner Bros suggested, "Generic Wizard Night".

The Underground restaurant is one of the first of a new trend of "pop-up restaurants" – dining experiences operated out of people's homes and advertised via Facebook and word-of-mouth. However, the publicity it has generated also brought it to the attention of Warner Bros.

Ms Marmite said: "I understand that you need to protect the rights but this is two dinners, one-offs, from which I am not making a profit, inspired by the books and the mentions of food in them. My daughter is a huge fan, even an obsessive."

Feeling the corporate might of Warner Bros is quite a surprise for the new chef. When she hosted a Marmite night at The Underground Restaurant, with the spread included in every dish, the company was more than a little pleased. Instead of warning her about its copyright position, it made sure she was stocked up with plenty of marmite – and all for free.