Hi arpconsulting,
If you are selling goods in to the UK and the value of the goods is over £135 then there will be a requirement to register for VAT in the UK if you are the importer of the goods in to the UK.
If you are dropshshipping goods from the EU in to the UK then again it will depend on whether you are the importer of the goods in to the UK.
If you are the importer in these scenarios then there will be an instant requirement to register for VAT in the UK.
If you are selling goods to individuals in the UK below a value of £135 then there will be a requirement to register for VAT in the UK upon the first sale made.
If you are sourcing the goods from the UK then you will be making taxable supplies in the UK and again there will be a requirement to register for VAT upon the first sale made.
Please see the links to the guidance below:
VAT and overseas goods sold directly to customers in the UK
Who should register for VAT (VAT Notice 700/1)
Thank you.