It's a condition of entry into Naval Service that all joiners must have a valid passport. This is mentioned in the 'call in' letter to sit the Recruiting Test at the start of the application & the Pre-entry brief letter at the end of the application process & is usually stated by the Careers Adviser at selection interview.
Those who do not have a passport & have a provisional entry date should speak to their Careers Adviser without delay. If the AFCO advise you cannot join because you do not have a passport then they will probably not bid for an entry date until the valid passport is produced, so the waiting time for entry will start from scratch.
Those who can demonstrate severe financial hardship should either discuss the issue with the DWP if unemployed or their Careers Adviser as soon as practicably possible.
theres places you can go to get a passport/renewal there and then. the closest to me is liverpool but obviously depending on where you live thatll change. also you may have to travel and pay out a bit more money but under the circumstances im sure you can agree itll be worth it