Partnership income tax — salaries and interest as profit allocation

Two individuals carry on a catering business as an ordinary partnership in England. Their agreement allocates the first GBP 20,000 of each year's profit to one partner for managing the business and divides the remainder equally. They call the priority allocation her 'salary'. The year's profit exceeds GBP 20,000. How is her GBP 20,000 allocation treated for income tax purposes?