Surveillance equipment and hidden cameras are being bought by partners, who fear their other half could be having an affair.
The devices are worthy of appearing in a James Bond film, but here in Leeds, people are buying them in droves for matters close to the heart, according to one business.
Proof
The latest spy software is an SMS mobile phone text interceptor which sends copies of all texts sent and received by the person under suspicion.
It is quickly and easily installed and can provide the proof someone might need that their spouse is being unfaithful.
Hidden cameras, which can be installed in equipment which as a wall clock, smoke detector, DVD player or stereo system and can operate through a hole as small as 2mm.
Dave Allam, owner of The Spy Shop at Kirkstall Road, which he runs with son Nigel, said they were inundated with people wanting to buy detection devices.
He said: "We hear all sorts of sob stories, but of course I would never tell any of them. We do end up consoling some people.
"We sell an awful lot of spy equipment and devices which could easily catch out even the most discerning person. We have just sold three today.
"At one time affairs were arranged and carried out over the house telephone, now they are carried out by mobile phone and usually by texts, which are rapidly deleted, so there isn't a trace left behind – until now.
"The software we install enables copies of all texts to be forwarded."
Other implements sold include listening devices and bugging equipment, often bought by companies or businesses to keep a watchful eye on staff.
Mr Allam said the gadgets were all perfectly legal and easily fitted in residential homes without showing any sign of disturbance.
alison.bellamy@ypn.co.uk