Failed leadership candidate Lisa Duffy was having dinner with her staff in Bournemouth on Friday.
No action was taken against the curry house, which had completed pre-employment checks.
UKIP has long campaigned for tougher border controls to cut illegal immigration.
Jay Beecher, a spokesman for Ms Duffy, said: "Watching our chef running away into the night, his apron flapping in the wind, was a surreal moment.
"Politics can sometimes be such a stale and serous affair, so you have to see the funny side of things.
"In this case too, I couldn't help [but] be tickled by the irony."
The Border Agency questioned staff about their right to work and live in the UK.
Diane James was elected ahead of Ms Duffy to succeed Nigel Farage as the UKIP's new leader on Friday.

Pan gyhoeddwyd canlyniad y bleidlais gyhoeddus ym Mrwsel nos Fawrth, fe ddaeth Derwen Brimmon - coeden tua 500 mlwydd oed ger Y Drenewydd - yn ail i goeden 650 oed yn Wisniowa yng Ngwlad Pwyl.
Cafodd y goeden Bwylaidd 1,400 yn fwy o bleidleisiau.
Yn ystod yr Ail Ryfel Byd fe gafodd y goeden honno - Derwen Josef - ei defnyddio fel lloches gan deulu o Iddewon oedd yn cuddio rhag y Natsïaid.
Daeth Derwen Brimmon yn amlwg yn y newyddion pan gafodd llwybr ffordd osgoi'r Drenewydd ei newid er mwyn gwarchod y goeden hynafol yn dilyn ymgyrch gan bobl yr ardal a thu hwnt.
Cyhoeddodd Llywodraeth Cymru ar y pryd y byddai'r llwybr yn symud 15 metr o fonyn y goeden er mwyn peidio aflonyddu ar y gwreiddiau.

Lara Clarke, an amateur baker from the West Midlands, has baked this special Harry Potter cake.
In the past she has also baked the Weasley's flying car and the Hogwart's library.
Many other bakers around the world have also made cakes to celebrate JK Rowling's special day.

He is known for frank - some would argue brutal - descriptions of sexuality and alienation.
One of France's best-known authors internationally, he also wrote the books Atomised and Platform.
Houellebecq, 52, won a court case in 2002 against Muslim groups who accused him of insulting Islam.
He said he felt contempt for Islam, but he was cleared of inciting racial hatred.
The Map and the Territory, first published in French in September, satirises the Paris art world, telling the story of a misanthropic artist who achieves critical and commercial success by photographing old Michelin maps.
It also features a badly dressed, drunken writer by the name of Michel Houellebecq who becomes the victim of a grisly murder.
"Among all the people who are going to discover my books thanks to this prize, I hope I won't disappoint them and they'll be happy," the author told French media.
He has twice come close to winning the Goncourt Prize before, in 1998 and 2005.
Immigration officials raided an Indian restaurant during a UK Independence Party conference dinner, sending the chef "running into the night".
[NEXT_CONCEPT]
Mae coeden dderw hynafol wedi dod yn ail yng nghystadleuaeth Coeden Ewropeaidd y Flwyddyn 2017.
[NEXT_CONCEPT]
The author of the Harry Potter books, JK Rowling, is celebrating her 50th birthday today.
[NEXT_CONCEPT]
The controversial writer Michel Houellebecq has won France's top literary award, the Goncourt Prize, for his book The Map and the Territory.