Official UK position (response to email to Passport Office, April 2015)
"Dear Mr ...........
Thank you for your enquiry.
Her Majesty's Passport Office will only issue second passports for extensive business travel or extensive business travel to incompatible countries.
Your application will be reviewed by the Passport Office for eligibility.
To obtain a second passport your application must be supported by a letter from a Senior Manager by whom you are employed detailing the necessity for this passport. This letter must be on company headed notepaper.
If you are self employed a letter from a client, on company headed paper, explaining why a second passport is required should accompany the application.
If you have already been issued with a second passport and wish to renew either your original or second passport you must support your application with a letter from your employer/client detailing the necessity for two passports.
In order to apply you can complete the form online at
http://www.gov.uk/apply-first-adult-...for-a-passport or you can pick up a form from selected Post office Limited branches, or request a form from the website
www.gov.uk/get-passport-application-form. The forms will be posted out for you to sign and submit with the supporting documentation.
You will need the following documents:
1. Passport Application form completed in black ink, capital letters (if completing a paper application form).
2. Sections 1,2,3,4,5,9 and 10 need to be completed. Section 1 needs to be completed as a first adult unless you are applying to renew your second passport.
3. Section 10 must be completed.
4. Two recent identical passport sized photographs (only ONE certified at the back as a true likeness of applicant) these must comply with our photo standards. Information can be found on-line at the following link:
https://www.gov.uk/photos-for-passports or detailed in the application guidance booklet (enclosed with the application pack)..
5. Name change document if name has changed.
6. Fee of £72.50
7. Current passport* or your Birth Certificate (Full Birth Certificate if born on or after 01/01/1983) if your current passport is not available.
8. Letter from employer stating the need for a second passport.
We would advise you not make any travel arrangements until you receive your passport.
*If you are required to use your current passport for travel whilst you are applying for a second passport, you need not submit the same with your application. Please enter your current passport number in section 3 of the form and give details in section 8 as to why your passport is not available.
Alternatively, you may enclose a separate letter detailing your current passport number and why you are unable to submit the same.
Thank you"