The home secretary has announced plans to expand the security service MI5 by recruiting an extra 1,000 staff to help combat the threat of terrorism.
MI5 employs about 1,900 people
BBC News Online looks at what it takes to become an MI5 employee.
It is expected to take several years to find and vet the 1,000 new security services staff, who will principally be employed to carry out surveillance work.
Details of the new positions have already been posted on the agency's website after news of the 50% expansion was reported at the weekend.
The 1,000 new staff will bolster the 1,900-strong workforce already employed by MI5.
Where the service previously focused on Cold War and IRA suspects, it is now particularly keen on recruiting Arabic speakers to help focus on the threat from al-Qaeda.
Tapped phone calls
Successful applicants for language jobs, who will either speak a language as a mother tongue or as a graduate, will join a team of linguists whose job is to "translate and transcribe overt and secret information obtained in many different languages".
Most of the information to be translated comes from tapped phone calls and intercepted mail.
Linguist job requirements
Mother tongue knowledge or honours degree equivalent in required language
British by birth or naturalisation with close links to the UK
Good hearing (to be tested)
Other jobs advertised on the MI5 website include mobile surveillance officers, data communications technicians and developed vetting officers.
Graduates are invited to apply as "security service generalists".
Although some jobs sound more mundane than others, MI5 says some "operational work" is inevitable.
Its website says: "Admittedly, at some point in your career it's likely that you will be involved in some form of operational work - perhaps running agents...into and against a terrorist group."
'Security vetting procedures'
"Core working skills" required for all posts include analytical skills, decisiveness, self-reliance, initiative and communication skills.
Key "personal skills" include integrity and reliability, political sensitivity and personal impact and leadership.
Surveillance officer job requirements
Able to blend in, average height, build and appearance
Able to remain alert during periods of inactivity
Flexible and able to cope with frequent disruption
To apply for the jobs, potential candidates initially complete an application form and, if successful at that stage, have to pass "the same sort of aptitude tests that any large organisation might use".
Aptitude tests are "allied to a rigorous security vetting process".
Recruits then have to undergo a 60-day intensive training and assessment period, with no guarantee of a job at the end of it.
After this, the first six months of the job involves a formal training programme together with on-the-job experience before trainees become fully-fledged employees.
Starting salaries for graduate jobs are a maximum of £20,100.
'Competitive and rigorous'
One psychology graduate who has applied for MI5 twice, and who does not wish to be named, said she had found the process "competitive and rigorous" but that it had not put her off applying again.
On both occasions she progressed to the stage of psychometric testing "along with hundreds of others" at a testing centre.
She says this was "an achievement in itself".
She did not progress any further but was told there were several further stages before acceptance into the service including making presentations to recruitment staff.
She told BBC News Online: "There were about five stages in recruiting so it is rigorous but I wasn't put off by the competition - it's clear that they're trying to get a good range of people."