It is important to bear in mind that there is no sure formula for composing an invitation letter. Each application takes place in a set of unique circumstances varying from simple to complex, and no sample can aspire to address all of these. In general terms, the topics to cover are:

• Your own immigration status in the UK
• Your relationship to the applicant, if you are friends, then a brief history of your relationship
• Why and when you are inviting the applicant
• Evidence of your financial and employment history
• Evidence of your ability to accommodate the applicant
• Evidence that you have a basic understanding of the rules for visitors to the UK
• A reasonable estimate of what you expect the costs of the visit to be

Topics that would be irrelevant or inappropriate might include:

• Anything about your sexual relationship
• Any kind of assurance that the applicant does not intend on violating his/her visa (this is the applicant's responsibility, not yours)
• The applicant's previous immigration history
• The applicant's job or career - except as it pertains to your relationship

And finally these tips:

• Owing to the sophistication of forgerers, your attachments should be originals.
• We are now recommending that a photocopy be included with every original.
• When submitting original bank statements, the sort code and account number can be blackened out in order to prevent identity theft; this information can be given separately.
• When submitting original salary slips, the National Insurance Number can be blackened out in order to prevent identity theft; this information can be given separately.
• It is perfectly acceptable to give the applicant a sealed envelop with all your attachments inside. Mark the envelop "CONFIDENTIAL DOCUMENTS: To be opened by the ECO". And include a self-addressed envelop so they can be sent back to you.
• Don't overdo it with photographs and mementos
• If you opt to include email or chat transcripts, be VERY careful about what they contain
• If you have any questions whatever about what to put in your letter, consult an advisor. You can locate an advisor near you at the Law Society's "find a solicitor" site. Transpondia endorses this site as entirely trustworty.
• Take note that the sample correspondence on this site has been accessed over 100,000 times (as of June 2006). Accordingly, composing a letter verbatim from the text given in these samples might reflect adversely upon your credibility.