First you'll want to check if you need a visa to enter the UK.
- Nationals of the EU, Switzerland, and EEA countries will not need a visa, and are free to work and conduct business in the UK.
- Nationals from some designated countries such as USA may travel for tourist or business purposes under a visa exemption. The link above will detail what documents you need to provide in order to travel under a visa exemption.
- Other nationals will need a visa.
The rules for allowable business travel under a visa exemption are covered by the same rules as those travelling under a vistor visa. If you will be travelling under a visa-exemption and the conference is covering your costs in any way you should make sure to read the relevant section below.
You can only do certain academic or business-related activities [...] Check the full list of what you can do - it’s the same as what you can do on a Standard Visitor visa.
A standard vistor visa will be sufficient for the large majority of conference speakers and attendees.
The official information for this is the gov.uk site.
You can apply for a Standard Visitor visa if you want to visit the UK for business-related activities, eg: you’re coming to the UK for a conference, meeting or training.
You shouldn't have anything else to do.
You are not allowed to work in the UK as a visitor, however it is permitted for your travel, maintanance and accomodation cost to be covered. The vistor rules sections V 4.3 through to V 4.7 cover this in more detail.
Relevant guidelines here are:
V 4.3 A visitor’s travel, maintenance and accommodation may be provided by a third party.
...and...
V 4.7 The applicant [may receive payment for] reasonable expenses to cover the cost of their travel and subsistence.
Note that if the conference organisers are providing accomodation and/or living costs while in the country you should seek a written confirmation of this from the organisers, to provide to immigration officials if requested:
V 4.4 The third party may be asked to give an undertaking in writing to be responsible for the applicant’s maintenance and accommodation.
Make sure that the confirmation comes from a UK-based organisation. If the conference organisers themselves are not UK based you should discuss this with them to find a way to accomodate this requirement.
If you're in any doubt about what might consitute "reasonable expenses" you might also consider requesting that the conference organisers make any flight, accomodation, or related purchases up-front, rather than via reimbursment of cost.
If you will be receiving any kind of payment for speaking which may not fall strictly under "reasonable expenses", then you should instead seek a "permitted paid engagement" visa.
This costs £85, and requires that you "are invited by a UK-based organisation". The guidelines for permitted paid visas broadly appear to cover speaking engagements.
You can be invited by a UK-based organisation or client to [give lectures], as long as it’s not a part-time or full-time role.
Non-academic conferences are not explicitly listed in the PPE guidelines, but the intent does appear to cover them.
Either way, your PPE visa application will be in advance of your visit, rather than at point of entry, so you won't be running any risk of being turned away at the border.
Hello I am a farmer in based in Botswana and I wanted to attend a conference in the UK what will I need to provide as prove?I will be covering all the costs for food,flight tickets, accomodation and transport the trip only lasts 4 days help organize myself please