This isn’t network performance but the all-important ‘man in a van’ performance. While everything else is constantly improving, usually because Moore’s law is cranking up the intelligence or driving down the cost, the same can’t be said for all of the day-to-day stuff like line installations and fault-fixing.

And it’s this, it turns out, that's not only the big cost-centre in the fixed line telecoms story, but is the critical element in the oft-mentioned ‘customer experience’. Faster broadband is all very well, but installation or fault-fix delay simply trumps everything else when it comes to complaints and the likelihood that the customer will churn to another provider

And that’s why Openreach’s performance here is critical. It not only provides underlying installation and fault-fixing for BT’s retail and business customers, but to all the UK’s competitive telcos which buy its copper or its broadband services and to their customers.

That was the idea: BT was allowed to separate infrastructure and services in return for its own freedom to price and offer services in fair competition with the rest of the UK market.

But separation is not enough: there still needs to be some strict discipline if the infrastructure entity is to be kept on the straight and narrow.

An apparently growing tide of complaints has caused Ofcom, the regulator, to get the big stick out, even though some of the sub-bar performance can be attributed to one-off events, such as disruptive weather patterns.

So we have some new ‘or else a big fine’ requirements. Openreach has to repair 80 per cent of the standard problems within two working days and for line installations 80 per cent of its customers must receive an appointment within 12 working days. Failure to meet these targets will result in big fines.