Sharron runs a hair dresser business. A year ago, she took on Allen as an apprentice and paid him an apprentice salary. Allen had just graduated, he was polite to customers and was committed to doing his job well. While Sharron allowed Allen to work on her customers, such as hair washes, trims and basic cuts, Sharron always checked everything carefully. It was no secret that a few of the best hairdressers in the area were trying to entice Allen to work for them for much better pay than he was getting from Sharron. When Sharron became aware of this, she told Allen that if he stuck with her business for another year, she would let him take it over and share the business profits with him. Allen decided to keep working with Sharron, despite knowing that other hairdressing opportunities were available to him.

A year later, Sharron retired. In the meantime, one of Sharron's customer's sons Dimetri, who had been working as a hairdresser at another salon, expressed interest in taking over Sharron's salon. Sharron decided to hand over the business to Dimetri, largely because he was older, more experienced, and was also very popular in town. Allen was disappointed as he thought the business would be his. He confronted Sharron about her promise, but Sharron simply brushed him off and said Allen did not provide any consideration for the promise.

Advise Allen whether he can enforce the promise made by Sharron.

Please use case law to support your answer.