Could it be the number of candidates at a general election for the whole UK. Minimum 1 candidate per constituency ?
Is it how much the Tories claim to have spent in each constituency during the GE, compared to what they actually spent?
Is it the numbers in attendance at the European Parliament during sittings - 755 being the minimum to approve any laws or proposals?
The size of constituency, measured in hectares ? The smallest is Islington north at 735 hectares, I don't know which is the largest.