Years of sexual abuse scandals have hit the image of the Catholic Church and its priests face long hours and modest wages.
So what drives the young men who want to be ordained?
Just around the corner from the designer shops and fancy restaurants of London's Kings Road stands Allen Hall.
It is home to a small number of men in the middle of a journey.
The residents of Allen Hall, a Catholic seminary, are spending up to six years preparing to become Roman Catholic priests.
The student priests, known as seminarians, believe they are answering God's calling in dedicating their lives to the work of the Church.
Just reaching the seminary door has been a struggle for some.
"I never really thought of myself as a priest. I thought I had as much chance as becoming an astronaut," says first-year student Rob Hunt.
"I was a roadie for a band and hung out with them for about 10 years. It was a different life. That's a party lifestyle, as you can imagine."
Now the 42-year-old has images of St Therese of Lisieux and the Virgin Mary adorning his room. "I always say I've got pictures of women all over my wall just to wind people up," he says.
The seminarian was brought up in a Catholic family but drifted away from the Church in his teens, until a complicated relationship made him think again about his faith.
"I paced around, agonising over it. It became about something deeper, me and my soul. It's as if I was stung back into belief in a way. As if someone prodded me and said you've got to think about how you live your life."
Most of the student priests at Allen Hall have experienced some difficulties embarking on their chosen life.
"My faith has always been incredibly important to me," says final-year student Andrew Connick, "but extremely private."
It was at university that Andrew found the courage to speak to the chaplain about his desire to join the priesthood.
"Going to speak to him was very difficult for me. It took me ages. I didn't speak to anyone about it before, but I'd always known there was something there, but I hadn't accepted it."
Priests play a central role in shaping the lives of the five million Catholics in Britain. They administer the Church's sacraments and pass on its teachings.
Yet for all their importance their numbers are falling.
Only 19 men were ordained in England and Wales in 2010, with the fallout from abuse scandals thought to be a contributing factor.
But the staff and students of Allen Hall see the natural doubts and anxieties the men experience as the reason more reconsider their futures.
The seminary acts as a testing ground to discover what the men believe God is asking of them, a process known as discernment.
If a student does not become a fully ordained priest it is not seen as failure, but providence, or God's will.
The long shadow of the abuse scandals informs the procedures employed by the Church.
To be enrolled in seminary, prospective students now undergo vigorous psychological profiling.
"They give you a form to fill in with info about your background, your past, what you think of this, of that, your family. Endless questions," says Hunt.
"It's all part of the screening process. Considering what's happened in the Church, they really don't want to make that mistake again."
The profiling is to assess the motivations of the would-be priests.
"The abuse scandal hasn't affected how I think of my vocation," says fourth-year student Mark Walker.
"But I am aware of how frail every priest is. There is a tendency to put priests on a pedestal, to be holy, which is right, but equally priests would describe themselves as flawed people, sinful people just like everyone is, but trying their best to be holy priests."
These doubts and anxieties can remain with a priest even after ordination.
"It's the loneliness that is most difficult to deal with," says former Catholic priest Jimmy O'Brien.
O'Brien had doubts after joining a seminary in Ireland as an 18-year-old in the 1970s, and found they never really left him. After working in a parish for 10 years following his ordination, he left the priesthood.
"You begin to realise that you will never experience family life, you will miss out on that companionship and that is hard."
Still a devout Catholic, O'Brien has now been happily married for 21 years and believes that the bar on priests marrying is one of the main reasons the number of priests ordained has been falling.
"It's a strong argument to say a married man can offer more. At 18 I wasn't equipped or worldly-wise. Prospective priests should be given the opportunity to live in the real world," he suggests.
The curriculum at Allen Hall recognises the need for a more open environment for students to develop.
Students now learn about celibacy in the first year of training. They discuss the positive role they believe it plays in setting the priests apart from lay people.
"You don't switch it off. You are still a man. It's how you channel that energy really. Sexuality is a very powerful force and if you don't deal with it, it will get you," Hunt concludes.
O'Brien agrees with the attempts at modernising but thinks more needs to be done to encourage men back to the priesthood.
"There has been such bad press. Most priests are committed men of deep faith but they don't get recognition because of the negative images."
The issue of not being able to marry is also discussed in Allen Hall's classrooms. For Hunt the issue is simple.
"To me it's practical, we're not available. We don't own our own lives any more, we live for others."