The Secret Tourist (BBC1, 9pm); Undercover Boss (C4, 9pm); The Hotel Inspector (Five, 9pm).

THURSDAY has been designated investigation night on the TV. While the hoteliers in need of assistance in The Hotel Inspector know full well the identity of the person coming to scrutinise them, Undercover Boss and The Secret Tourist both employ clandestine operations to uncover the truth.

Matt Allwright heads up The Secret Tourist, BBC1’s new consumer show that “has the holiday from hell so viewers don’t have to”. How thoughtful of them.

The idea is that the programme sends families to investigate and report on conditions in different resorts, including a hotel in Sharm el-Sheikh, one in the Dominican Republic and another in Turkey.

Joining them is environmental health expert Dr Lisa Ackerley, who’ll help them gather evidence from areas including swimming pools, hotel food and drinking water, cleanliness of rooms and the safety of children’s play areas.

Then Allwright takes their findings to the people responsible.

All that plus reporter Carole Machin on holiday scams, cons and rip-offs, as well as suggesting what can go wrong on holiday by examining the potential dangers in hiring jet bikes, mopeds and visiting a doctor abroad.

The thought of all those problems makes you wish that volcanic ash would cause your holiday to be cancelled in the first place.

Allwright reckons he’s stayed in “some really ropey” hotels. “I do a lot of travelling and I’ve stayed in some absolutely dreadful places,” he says.

“But there’s a difference between being a lone traveller – and kind of putting up with what you get because you know you’re not going to be there forever – and taking your family somewhere.

“When you’ve got kids (he has two), somebody not to make you ill and to look after your kids.

“It’s pretty despicable that people are as negligent as we see in the programme when there’s so much at stake for a lot of people.”

AFTER 80 years in business, Harry Ramsden’s fish and chip restaurants are facing the dual problems of the recession and increased competition.

New chief executive Marija Simovic becomes the Undercover Boss to find out what’s happening in the business.

Stationing herself behind the deep fat fryers, she’s determined to work out where the business is going wrong, and whether its fortunes can be be turned around.

Visiting three branches undercover, Marija has to temper her natural managerial impulses as she shadows a young assistant manager, two waitresses at the company’s busiest outlet and an empty restaurant reliant on pensioners.

She comes up against broken machinery, outdated decor and general disrepair.

How will she feel about the company at the end of her time undercover and how will employees react on learning the new trainee is actually their boss?

OVER in The Hotel Inspector, restaurant expert Alex Polizzi is in Brighton at the Artist Residence Hotel, which is being run by a 21-year-old student. The reaction from guests would appear to have been less than enthusiastic.

This isn’t perhaps altogether surprising when you learn that the breakfast buffet of Weetabix and aerated bread is a tribute to the Russian artist Kandinksy, who only ate cereal and toast.

As you can imagine, Polizzi doesn’t hold back on telling the young owner exactly what’s wrong with his hotel crossed with a gallery. It all makes for very watchable TV, but would you want to stay there?

you’re so responsible for everything. You save up for these holidays and wait for them all year, and then you are trusting