What size breaker do I need to supply a 63A consumer unit

We have no electricians here familiar with UK standards, appears that a 100 amp main is typical for a 63 AMp Consumer Unit, see:

Consumer Unit 12 Way 63 Amp Dual RCD & 100 Amp Main Switch - Consumer Unit 12 Way 63 Amp Dual RCD & 100 Amp Main Switch - Consumer Unit Dual RCD 17th Edition (2x RCDs & 1x Main Switch) - Consumer Unit - Expert Electrical