Citizens of most countries (like India, Srilanka, Pakistan and many more) will need a visa to visit UK. It is not a part of Schengen countries. Also note: if you intend to return to Netherlands after your visit to UK, you will need to have a visa (or a Residence Permit) that allows reentry to Netherlands (Thanks to Abhinav for this note – got it from one of his comments in another topic)!!
The UK visitor visa application should be submitted online and then to give the biometric information (i.e. thumb impression etc) and passport submission, every applicant should personally go to the UK visa application center.
Applicants in Netherlands have 2 options to give information and submit passport. Go to:
- Amsterdam: costs about € 175 for a 6 months validity, multiple entry visitor visa.
- Dusseldorf, Germany: costs about € 100 for a 6 months validity, multiple entry visitor visa.
After submission, processing will take about 2 to 3 weeks depending on the peak season (June mid to late August is peak period). During this 2 to 3 weeks, since the passport will be with the UK embassy, you cannot travel to any country outside Netherlands (Residence Permit is valid only in Netherlands).
If you wish that the passports be returned to you via courier, you may request for it at the time of application submission itself by paying a fee (in cash in Germany; I think €30 per family) or you can personally go and collect.
For further details, taking an appointment etc, visit the following sites:
https://www.visa4uk.fco.gov.uk/ – Application submission
To avoid the issue (and tension) of not having the passport for 2 to 3 weeks, in case you are still in your home country or visiting there for a few weeks, you can consider getting the visa done over there!
Disclaimer: This is my best effort and personal opinion only. No responsibility will be taken for any inaccuracy.