Last week my brother and I spent a couple of days in Durham.

We both had some time off work and he'd been to university there, so we fancied another look around.

The weather remained glorious and ideal for walks along the river, wandering though the cathedral grounds or a beer in the sun outside some of the pubs he and his friends used to frequent.

What everyone who arrives in Durham by train must notice is how immediately striking it looks. That sets it apart from many other places - including other university cities.

Oxford and Cambridge have their elegant colleges, parks and churches of course, but they're all a taxi ride from the nondescript parts of town where the railway stations stand.

But even before you've got off the train in Durham you're struck by the sight of the enormous cathedral, looming up as if keeping watch over the entire area.

It's pretty big now - but how much bigger it must have seemed in the centuries before high-rise flats and office blocks.

The other noticeable feature of Durham was the number of shops that stood empty.

In this respect it is just like other UK towns and cities. You don't have to go far to see examples of high streets that are being deserted by everyone except hairdressers, nail bars and charity shops.

in 2011 Mary Portas was appointed by David Cameron - who some may remember as prime minister - to investigate the problem and come up with recommendations for a solution.

But it hasn't helped. In the last 10 years 11,000 high street outlets have vanished.

House of Fraser in Carlisle is only the most recent victim. Poundworld, Mothercare and Marks & Spencer are all closing branches.

Internet shopping, less disposable income and the price of parking are all suggested causes, and probably aren't the only ones.

But it's the suddenness at which the change has happened that comes as a surprise.

Perhaps it shouldn't, because these economic changes often take place with dazzling speed.

Former jewellery tycoon Gerald Ratner knows this more than most. In April 1991 he notoriously gave a speech in which he described in colourful terms the poor quality of his products, and must be kicking himself daily ever since. In less than 18 months he and most of the shops had gone.

One of the cities that has changed most in the last few years is Belfast, in what's being described as "the peace dividend".

In the days before the terrorist ceasefire, the peace process and the Good Friday Agreement, Northern Ireland boasted a lot of small, independent shops that closed early on Wednesdays.

Belfast had the likes of Marks & Spencer, BHS, C&A and Littlewoods - but at one time they were those firms' only branches in the province.

It didn't have Debenhams, Next or Gap. McDonald's reached Moscow before it reached Belfast. The city centre's bookshops and music shops were all one-offs.

Then Waterstone's, HMV and the Virgin Megastore arrived, and the one-offs all soon closed.

Not long afterwards the big four supermarkets of Tesco, Asda, Sainsbury's and Morrisons all piled in, killing off smaller outfits and local chains. Very quickly it came to look a lot like anywhere else in the UK.

Of course the big shops were replacing the old ones, so there were still jobs to be had.

The owner of one bookshop became a manager in Waterstone's - the very place that had once terrified her. Those who worked in Golden Discs or Caroline Music may have found jobs in HMV.

That's not the case with this latest change. We all lament the demise of favoured shops, but it's the people who work in them that will feel it most painfully.

According to the British Retail Consortium, nearly half a million people are at risk of losing their jobs due to the closures of high street stores.

And 70 per cent of them will be women. Part-time jobs in sales or on the shop floor allow women who have to cope with child care or looking after the home to earn as well. Those are the positions that will be first to go.

Parents worry about the amount of time their kids spend online. But maybe they should consider reducing their own time in front of computers.

Instead of ordering everything on the internet, visit your town centre in person.

Get some fresh air and exercise, have a browse and rediscover physical, human shopping.

It's not as if it's too cold or wet at the moment.