Imagine a government that makes the following reasoning: approximately 5 per cent of the population suffers from lactose intolerance and some of them don¡¯t know it.

If you are one of these few and you eat some cheese or drink some milk, you may fall ill.

Solution: ban the production and sale of milk and cheese ¨C or at least make it absurdly difficult and expensive. Problem solved!

Does this seem stupid? Well, tell that to David Cameron. Because this is exactly what his government has done regarding travel to the UK for millions of non-Europeans.

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If you want to visit Britain for a few days ¨C perhaps to enjoy its famous fish and chips ¨C or if you are invited, as I was, to give a talk, you¡¯d better be a European citizen.

Otherwise, you will find yourself spending more money and time getting a visa than you will on the trip itself.

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I am a European citizen, but my wife is not (although she is my wife and therefore she has permanent residency rights).

I also happen to suffer from a severe disability that hasn¡¯t prevented me from being a staff scientist at the Spanish Research Council, a hard-working member of the European Parliament for nine and a half months, and now a member of the regional parliament in Arag¨®n, Spain.

Alas, my disability does prevent me from travelling alone without the assistance of my wife.

Recently, I was kindly invited by Philippe Marliere of the University College London European Institute to give a talk about the political movement Podemos, which I am part of.

I was thrilled to visit London again. I love the city ¨C and not only because of its amazing accessibility for wheelchair users.

When I looked into the visa procedure for my wife, however, my enthusiasm began to wane.

The first thing that surprised me was that the whole process is now contracted to a commercial company.

But if you think that this might mean that getting a visa is similar to changing from one mobile phone company to another, then think again. It is much worse.

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You need to register an account online and spend endless hours filling in a ridiculous 10-page form, which requires you to scan every official document you ever obtained (as well as to complete some compulsory fields that leave you with a choice of hiring a secretary to perform a detailed investigation of your whole life, or lying).

If you think I am exaggerating, just try to produce a list of all trips you have made outside your country of residence in the past 10 years ¨C including the day you left and the day you came back.

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After this extremely important and exciting task (I estimate it took me at least a whole afternoon ¨C and remember this is for a three-day trip, and I do have a day job), you must pay ?85 (more than the price of my wife¡¯s Ryanair ticket) and book an appointment at your closest ¡°visa application centre¡±.

Wait ¨C a visa application centre? Yes, and in Spain there is only one. It is in Madrid, more than 300km from where I live.

The whole thing ¡ª trip to Madrid included-¡ª can take up to three weeks.

But only if you need to keep an eye on costs; if money is no object, then I have some good news: for a not-so-small fee, another private company can speed things?up for you.

At this point, I cannot resist quoting a very interesting part of the ¡°How to apply for a UK Visa¡± guide:

¡°If you are eligible and wish to purchase access to the Premium Lounge, a Super Priority Visa, Priority Visa, Return Courier and/or other additional services, click Added Value Services and pick from the list. If you apply as a Group/Family, please note that you need to purchase one added value service for each member of the group. You can purchase these services by adding to your cart; then review your order and checkout.¡±

Nope, this isn¡¯t Amazon. It¡¯s the process for securing a UK visa.

When I realised all of this, it was already too late for my trip. However, I once managed to enter the UK with my wife and without a visa, thanks to a common-sense decision by an airport official. So I asked UCL for a letter of invitation and decided to try my luck.

As you might have guessed, this time we were stopped at the airport and told we could go no further.

I apologised to the organisers of the event, which was due to take place this evening, and to those who were planning to attend, and have decided that I will not visit the UK again as long this madness is in place.

Because of a tiny proportion of travellers who may try to stay in the UK after entering as tourists ¨C something which is OK with me, but which I accept that a democratically elected government might want to prevent ¨C or because of an insignificant number who could be engaged in criminal activities or pose a security risk, Cameron is effectively choking non-European tourism as well as cultural, political and scientific talks and events involving non-European guests.

I didn¡¯t want to believe it, but he has banned milk and cheese.

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Pablo Echenique is one of the five MEPs elected by Podemos in the 2014 European Parliament election. More information about the talk he was due to deliver at the UCL European Institute this evening can be .