Long overdue - 70mph is an anachronism.
In the right conditions I regularly drive at 90mph on the motorway and on more than one occasion have gone past police cars. They tend to be pragmatic and see exceeding the ridiculously low limit in the right conditions not to be worthy of pulling people over.
Car are safer, more reliable, brakes are very efficient and our cars run on decent rubber than when the limit was set over 50 years ago. But, some will say, people are the same - but they're wrong. People adapt to their environment, and as the roads have become busier and quicker people have adapted.
Yes there are very poor drivers out there, but there will be whatever the limit.