If you have turned into a VAT registered trader in any eu country that levies vat including the UK then you would need to submit vat invoices of your suppliers for successful vat refunds and you will surely need to conduct vat registration check to deal with genuine businesses. However, if the vat numbers of your suppliers turn out to be incorrect then it would adversely affect your chances of receiving a vat refund and you could also get penalized in the process.
It is anyway quite easy to check vat registration numbers of any vat registered business situated in the UK or in fact any other eu country that has adopted the system of value added tax. This could be very crucial if you plan to import goods into the UK where you might be a vat registered trader and plan to apply for vat refunds for vat already paid on those goods. In such a case you might find yourself in deep trouble if the vat number printed on the vat invoice of your supplier or vendor turns out to be bogus or an expired one.
If a dubious supplier has provided you with a fake registration number then you might find out the truth only when you try for a vat reclaim on goods or services imported by you in the UK. This would result in your vat refund application being rejected as well as ending up on the wrong side of HM Revenue and Customs or hmrc that looks after customs, excise and vat duties in the UK. Each future vat refund application submitted by you will now be looked at with grave suspicion for no fault of yours except for the fact that you forgot to conduct a vat registration check before importing goods or services into your country.
You can easily visit the website of the European Commission that handles all eu vat issues that govern all eu countries that follow vat. You can use this link to directly end up at the registration checking section of Europa: https://ec.europa.eu/taxation_customs/vies/vieshome.do?selectedLanguage=EN. You will need to mention the complete vat number including the member state name, which usually is mentioned in the first two characters. You will also need to submit your own vat number along with your state code and will receive the results within seconds.
Alternatively you can also call up the hmrc office number if you are a vat registered trader in the UK. The phone number is 0845 010 9000 and you can call during office hours to again find out the validity of any vat registration number within seconds. You can continue with the deal only when you are convinced that the opposite party is truly a genuine vat registered trader in that country. Since vat refunds take a long time to materialize it is always better to take precautions instead of being shocked after a few months after filing for a vat refund, by which time the dubious supplier might have changed the business name or address.
It is always better to check the vat registration number of any supplier or vendor before you start doing business with that firm. Since any loss of refund or penalty arising out of a bogus or expired vat number will have to be borne by you, it is in your interests to conduct vat registration check so that you end up dealing only with genuine businesses.