Image copyright Getty Images Image caption British women are being conned by internet fraudsters posing as soldiers

"I had lost my husband to cancer and for a year and a half I didn't know what to do with myself.

"I've got to move on, I thought. So I joined an over-50's dating site."

Jean - not her real name - was soon contacted by a man named "Alex", who claimed to be a soldier in the US Army. He said his wife had left him, that he was raising his teenage son alone, and that he was soon leaving for a tour of Afghanistan.

"We struck up a friendship, talking by instant message. He said he was going to come and see me. He said all the right things."

Weeks into their blossoming friendship, Alex claimed his son had changed the PIN for his cash card and he was in financial dire straits. Jean offered to help and sent Alex some money. But it wasn't a one-off favour.

Costly sob story

He told me he had gone AWOL... and was in a military prison and needed money to get out "Jean", Victim of dating fraud

Speaking to the 5 live Investigates programme, Jean recalled how Alex's requests for money began to snowball: "It went on and on. I kept helping him and his son with various things - domestic bills, school fees and things like that."

"At one point, he [Alex] told me he had gone AWOL and was back in Los Angeles, in a military prison, and needed more money to get out."

"I ended up giving him more than £100 000."

Jean is not alone and is one of a rising number of women to fall victim to this particular form of online dating fraud, where the scammer poses as a US soldier - they often say they're stationed at a US base in the UK, to inspire hope that a relationship is possible.

The yarn spun by "Alex" - deserted by his wife; single father - is a common one. A desperate request for money is inevitable.

The fraudsters behind the scam are often based in West Africa - Nigeria in particular - and it can prove very hard for authorities to track them down.

They will sometimes use the names of real American soldiers - including those killed in action - and steal photos from military websites or the social media profiles of real soldiers to make their own dating profiles appear legitimate.

This US soldier-in-distress online dating con has come to the attention of the United States Embassy in London.

Scam on the rise

Speaking to the BBC, Consul General Derwood Staeben said people contacting the embassy to report dating fraud was now a daily occurrence:

Image copyright Getty Images Image caption Online dating scammers often send gifts to their victims to convince them they are legitimate.

"When I arrived at my post two years ago, there were two or three a week. We've had more than 10 in the last five days."

"In the last 10 months, here at the embassy, we've logged around 450 phone calls and just shy of 2,000 emails."

This rise has also been recognised by the National Fraud Authority - earlier this year it reported a four-fold increase in the number of people reporting online dating fraud to the Action Fraud helpline.

Rebecca - not her real name - is another victim who was sweet-talked by a fake soldier named "Charlie". She will not reveal how much money she has lost but says she is in a lot of debt as a result of the scam.

They take weeks - in my case, months - to build up trust, asking you about your family and life, and making you feel loved "Rebecca", Victim of dating fraud

She says she fears opening her mail, or answering her phone, as she doesn't know how to repay the money she borrowed to lend to Charlie.

Like fellow victim Jean, she said the men posing as soldiers really know how to exploit the emotions of the women they hope to con.

"I was recently in hospital for an operation and on my way down to the theatre, he was texting me to say he was going to pray for me and he would soon be with me to take care of me."

"They go to great lengths to appear realistic. Sometimes you even get gifts - I was sent flowers, balloons and teddy bears, and would receive poems and emails every day.

"They take weeks - in my case, months - to build up trust, asking you about your family and life, and making you feel loved.

"Then they tell you a sob story about them being left alone with a child - they even send text messages and emails supposedly from their child."

Elaborate plan

One of the common requests from the bogus soldiers is to ask the women they are conning to apply for leave on their behalf, so that they can come and visit them.

Image caption The US Embassy in London has seen a steady rise in people reporting dating fraud.

This follows an elaborate set-up, where the women are asked to complete official-looking paperwork - and send a fee, which they are told will be refunded.

This is what happened to Rebecca. She was even having daily telephone conversations with a man she believed was a US Army benefit officer, to help process Charlie's leave application - this was in fact another scammer posing as a US Army official.

The US Embassy says that while specific procedures for requesting and granting leave differ among the branches of the US Armed Forces, the request and authorisation to take leave is between the individual service member and his immediate command - family, friends and third parties are never involved.

Alarm bells began to ring for Rebecca when she was sent what was purported to be US Army documentation to convince her that Charlie was able to repay her the money she had been lending him. It claimed he had assets worth $1.4m (£890,000).

"No soldier has that kind of money," says Rebecca.

"That's when I rang the US Army and they told me they hadn't heard of him."

Facebook campaign

While researching this story, the 5 live Investigates team spoke to dozens of women ripped off in this way. The majority are too embarrassed to share their story publicly but Rebecca and Jean were keen to speak, to try to ensure other women did not suffer the same fate.

Today Rebecca is involved in a Facebook campaign, titled 'Stop the US Army Dating Scam' in the hope that she can warn other women of this costly hoax. Since starting the campaign, she has been contacted by more than 240 other women who have also fallen victim to phoney soldiers through online dating sites.

Not all of them have lost cash but many have bought laptops, mobile phones and cameras, which they sent to addresses where the "soldiers" said they had friends.

The US Embassy says anyone who has been a target of dating fraud should report their case to their local police force. Rebecca reported her case but was told there was no chance of her ever getting her money back.

However, in Jean's case, police did manage to trace some of the money she sent to accounts in Nigeria and California. They recovered just over £13,000 - small consolation when the total sum she sent was close to £100,000.

A year on after being caught out, Jean is utterly distraught knowing she was conned and feels she has let her family down.

"What hurts the most is that when my husband died of cancer, he put everything in order. He had arranged for money to be invested so I could draw an income each month and I could have a decent lifestyle. And I went and wasted all the money and that broke my heart."

"I have three teenage grandchildren. I like to help them out, give them pocket money. But of course I had to tell them about this and tell them that it meant I can't give them anything any more."

"I'm close to my family and I feel I let them all down."

"My son told me: 'How many times in life have you told us to be careful?' And now look what you did."

You can hear the full report on 5 live Investigates on Sunday, 26 September at 2100 BST on BBC Radio 5 live.

You can also listen again on the BBC iPlayer or by downloading the 5 live Investigates podcast.