Lindsay Lohan -- Bolts Outta London After Cops Storm Apartment (PHOTOS)

Lindsay Lohan and fiance Egor Tarabasov got into such a heated argument, cops in London kicked down their apartment door to check on them -- and now she's leaving town ... alone.

LiLo left her home Monday morning and headed to Heathrow ... after a tumultuous weekend. Officers responded to a call early Saturday morning to "a woman in distress" at Lindsay and Egor's pad. Scotland Yard tells us ... once cops got inside they say there was no one there -- but they eventually tracked down the couple, and determined both were safe.

No arrests were made, but our Lindsay sources tell us things have been bad. We're told she's telling friends the relationship is violent at times.

While Lindsay headed to the airport alone, it's interesting to note she's still wearing her giant emerald engagement ring. She also used a shirt with an E.E. Cummings poem on it for cover from photogs.

Very artsy exit.