Loan Interest query for property development business

A property development partnership buys a residential property to do up and sell. It borrows the money to buy the property via a mortgage. At the year end the property is unsold and is in the process of being developed.

Q. In calculating the stock figure to c/f then whilst all the material costs are included is the interest charged by the lender part of the stock figure or should it just be w/o to profit and loss in the year.?

Thanks for any help