Spam has become an unavoidable plague over the past few years. Anyone who has shopped online or signed up to a mailing list (whatever their age, sex or religion) is almost certain to find their email inbox bombarded with messages advertising everything from Viagra to venture capital trusts – sometimes in their tens or even hundreds every day.

Like many people, I try to keep this under control by keeping a secondary email account, which I use for my internet affairs, a solution that's far from ideal – as it becomes hard to pick out the handful of useful messages from the heaps of junk in this account – but one that at least ensures my other email account is kept relatively clean.

In recent months, however, spam has started to attack me on a new front – my mobile phone – and this time, I'm really not sure how to escape it. Nine out of 10 times, the messages are for chat lines or porn websites and while I'm no shy prude, I can't help blushing whenever one of these arrives while I'm sitting with friends or, worse still, in a meeting. Did anyone catch a look at my phone screen? Do they think I get these messages because I've been signing up to some depraved site?

Although many of the spam messages I get on my phone tell me that I can stop them by simply sending a reply containing the word "STOP", I'm always concerned that this could be a scam. After all, while it costs nothing to receive a text, you never know how much it's going to cost to send one back to an unknown number – especially from a company peddling porn.

This kind of spamming is so offensive, even when its content is not pornographic. The fact that these messages can find their way into the palm of my hand, against my will, is the ultimate intrusion – perhaps with the exception of one other nuisance, which has also started to trouble me in recent weeks.

Since I used a handful of comparison sites to shop around for car insurance and a personal loan, I have found myself bombarded with sales calls asking me if I've got what I wanted yet. Given that I used these websites expressly because I didn't want to find myself getting the hard sell from someone in a call centre in Swansea, it's infuriating that this is exactly what I have ended up with.

Sales calls and spam messages are all governed by strict legislation, but many of the perpetrators get around it by ensuring that there's a line on page 23 of their terms and conditions which explains just what you're getting yourself into – ie once you've clicked this button, you've given us permission to use your phone or email address to contact you whenever we like. And if we sell your information on to third parties, then they they've got a right to pester you too.

I doubt that many of these terms and conditions documents would stand up to legal scrutiny, but for the moment, most people are not losing much or any money as a result, so legal challenges have not been forthcoming. I put a big price on my privacy, but maybe others don't.

Until the Government or the regulators clamp down on this invasion, there are a few things that we can all do to make the spammers' lives more difficult. No company is allowed to send messages to your phone without your consent, so if you're receiving spam, report them to the regulator Phonepay Plus. Phonepay also offers a free text message service (76787), to which you can send an unknown five-digit text number and check how much you'd be charged for replying to it.

But the first line of defence, of course, is to be careful whom you give out your number to.