James is the bookies' clear favourite to become new leader at the Ukip conference later this week and, in a Q&A with this website, she explained her motives for standing.
She said, "Having seen where Ukip stands in the firmament of UK political life, I believe that I have the skill set, experience and knowledge to lead Ukip to even higher political achievements such as winning seats in the Westminster Parliament."
She does not see any danger of the party, post-Brexit, becoming redundant, saying, "Ukip is not a single issue pressure group or a 'movement'. It's a properly constituted political party which had the support of several million people at the last general election.
"Of course, leaving the EU is a key theme for Ukip, not least because the EU interfered in almost every aspect of a Briton's daily life. Let's not forget that our manifesto at the last general election was the most professional of all the major political parties.
"It was widely respected for being independently costed and our policies were detailed and explicit to such an extent that the Tory government has been stealing them (the two per cent annual commitment to defence spending for example)."
The 56-year-old added, "As Ukip leader I will make a commitment to building a policy team that continues this work because Ukip is a political party of substance and ultimately, over the long haul of the next few years', policy substance wins support and elections."
She also set out her vision for Ukip, saying, "If substantive policy development is a strong card for Ukip, working within the constraints of the real world is our card deck in a bankrupt two-party system where an unfair and undemocratic first-past-the post electoral system is close to bankrupting our country.
"For this reason, Ukip will campaign for proportional representation. As leader, my vision is for the party to continue to lead with innovative ideas driven by a professional policy team which includes the broader range of the talents that we have in the party nationwide.”
When asked what she would bring to the leadership, James said, "Is there anything 'new' in politics? I bring tenacity of purpose, determination for the party to succeed, a collegiate leadership approach which will leave Ukip as a political party stronger and more successful when I go than when I arrived."
She admits to "not being sure" how long she will remain an MEP, adding, "If Brexit comes before the end of 2019 and the present batch of UK MEPs are made redundant, no one will be happier than me."
She also laid out the party's future role in the European Parliament.
One priority will be "continuing to scrutinise every piece of EU legislation that affects the UK as long as we remain a member."
Another objective will be to "press at every opportunity to encourage the EU institutions to give Britain a mutually beneficial and fair trade deal when it is an independent nation state which does not contribute to the EU budget and which controls both its borders and its fishing stocks."
James represents the south east of England and is the party's justice and home affairs spokesperson.
After a 30-year career in healthcare she is, according to the bookmakers, the favourite to win.
In 2015 she caused controversy with a series of apparently admiring comments about Russian President Vladimir Putin.
She was reported as saying, "I admire him from the point of view that he's standing up for his country. He is very nationalist. He is a very strong leader. He is putting Russia first."
Nigel Farage announced his shock resignation as leader, days after spearheading a successful campaign to take Britain out of the EU.
Her only rival, fellow MEP Bill Etheridge, has accused her of not being "focused" on Brexit after she called for Ukip to select candidates for the European elections in 2019.
He said, "Her priorities seem to be all wrong. Instead of assisting the fight for delivering Brexit, she is talking about 2019 and the European elections. She is putting internal politics ahead of the people and what they voted for in the EU referendum."
The result of the contest is expected on 15 September. Ukip was the UK's third-biggest political party by vote-count in the 2015 general election.