Yet the broadcasting environment has changed beyond recognition in those 31 years. The competition we face has grown dramatically and with the launch of digital transmission it will become even more intense.
So the question for ITV is how to preserve a market-leading position when the market is in not so much flux, as convulsion. It's a scale of change that provokes fundamental reappraisal - with no taboos. After 31 years, of course, there are strong views and deeply held personal preferences and I wouldn't want it any other way. The fact that the Prime Minister should express a point of view on the scheduling of a TV programme signifies the saliency of ITV in our culture. But the question now facing us is a bigger one than the scheduling of particular programmes - it's how to preserve that saliency in a new broadcasting era.
First, a few facts to concentrate the mind:
l Between 1994 and 1997, ITV's peak time share declined from 44.3 per cent to 38.8 per cent.
l The 9.30pm-10pm segment is the biggest half hour in British television. Any competitive broadcaster must make the most of the inheritance from this peak volume of viewers. Yet from January to May this year, 27 per cent of the audience tuned to ITV in this peak segment tuned out at 10pm; that's nearly three times as much as the percentage drop for total television viewing. Thirty-seven per cent of our younger viewers defected at the same time.
l This is not because News at Ten is not a good programme. In my view it is by some way the best news programme on television, but viewers' behaviour suggests that the appetite for news at 10pm is not as great as for other forms of programming.
No decent business would ignore this kind of loss, especially when faced with an explosion in competition. Feisty and decisive management action is needed, even if it costs us some friends in the short term. ITV's economy is a simple one. Large, high-quality audiences beget advertising revenue. Advertising revenue enables future investment in quality programmes, which beget large and high-quality audiences.
Allow the audiences to drift away and the cycle would become a spiral. We have a strong public service remit, monitored by the ITC, which costs money to fulfil - more than pounds 800m in 1998, pounds 750m of it in originally home- produced programmes.
Allow the spiral to begin, and ITV's ability to sustain that kind of investment will cease.
By opening up a 10pm weekday slot, we can inject new vigour and variety into our schedule by effectively extending our peak time. There is, of course, a cost to this which is being borne by our shareholders as an investment in the future market position of ITV.
It's a calculated risk. We are a commercial network, so we do have responsibilities to the many people whose pensions are invested in ITV companies, but the good news is that their interests are not at odds with those of the viewer.
This is because advertisers - our customers - don't want to buy "lowest- common-denominator" audiences; so we have no commercial interest in supplying sheer volume of numbers at the expense of the composition of our audience. Our commercial imperative is in fact to push ITV upmarket and to appeal to younger, discerning viewers. There is no commercial benefit whatsoever in moving downmarket.
Most Independent readers get home after 6.30pm. But for the audience across the country there is a proven appetite for news in the early evening. This is where the highest-rating news programme of the day is currently sited. So, far from marginalising our news service, our plan to move it to 6.30pm will take it into the fray, to where more people appear to want to watch it. And journalistically the 11pm bulletin will be a more comprehensive round-up and analysis of the full day in Parliament (90 per cent of divisions have occurred by 11pm, compared to 68 per cent by 10pm), the full US business day and even the opening of the Eastern markets - increasingly relevant.
But to understand ITV's proposals it's necessary to get beyond the argument as it relates exclusively to News at Ten. It is not particularly about uninterrupted films, though it's fair to say that ITV duty officers receive many more complaints on these nights than on the occasions when we shift the news.
The proposed change in the architecture of the schedule opens up the late evening for new, high-quality programmes, including the hour-long current affairs programme commissioned last week from Granada Television and planned for transmission in 1999.
This will be made in conjunction with ITN and anchored by Trevor McDonald, the country's favourite newsman. It will be supplemented by a stream of 60-minute documentaries commissioned for 10pm, and comedy and drama from new writers more appropriate for a later evening slot.
ITV is a regionally based television channel. We're proud of that and consider it to be a competitive advantage in these days of increasingly similar national channel launches. 29 versions of ITV cater daily for individual regional interests and this will not change.
Broadcasting must be the most competitive market in the UK. All our competitors, including the BBC, have the flexibility to adapt their schedules to compete as they see fit. I hope it is not unreasonable to request the same degree of flexibility in the interests of a vibrant ITV. The end of News at Ten does, I agree, mark the end of an era. But eras end, and commercial organisations that fail to notice, end too.
Richard Eyre is chief executive of ITVReuse content