The Wiki page on Sri Lanka’s 14th Parliament doesn’t just list the party MPs are in, it lists what party they were elected under as well. There are so many crossovers, largely because the opposition is so deeply fractured. Traditionally, the UNP (despite also being involved in the 1983 riots) is the UNITED NATIONAL Party, ie, at election time, most minority parties come under their umbrella. Under seemingly permanent bad leadership, however, these parties have left the tent.
The TNA (Tamil National Alliance) was formerly an LTTE proxy party and then and now runs alone. Mano Ganeshan used to bring Tamil votes to the United National Front, but he’s left. The CWC (Indian Tamil party) always sits in the government, and never does much for anybody. So they’re obviously with the UPFA. The SLMC (Sri Lanka Muslim Congress) used to run under the UNF, but they’ve also crossed.
The Wiki shows 10 recent crossovers, and 16 of an older vintage that now call themselves the UNP (D). I think there have been 60 over the years. Please note that the pie charts above show only the crossovers from 2010, the bulk were actually before.
The other plausible opposition (which itself opposes the UNP) would be the JVP, born of the former mostly Sinhalese southern Marxist, Khmer Rouge style insurrection. They don’t seem to exist at all anymore, at least not in Parliament. The four JVP members sit with the DNA, the party former General Sarath Fonseka set up. But he’s in jail. The JVP lost their main face when Wimal Weerawansa left and now it has fractured again, somewhat invisibly because they don’t even have enough seats to divide.
Those are the visible, documented breaks, which are pretty bad. The invisible one is that the UNP is internally divided between a Sajith Premadasa faction and one of Ranil Wickremesinghe. The recent internal election didn’t do much to sort this out (with Ranil winning over the proxy Karu Jayasuriya) and party members physically protesting and being arrested. Indeed, Ranil now enjoys quasi police (and road paving) support in holding the UNP headquarters, as his opposition is a boon to the government.
As mentioned the JVP is also fractured, and other parties have either crossed en masse or split and crossed in parts.
The Blessing Of Bad Opposition
President Mahinda Rajapaksa is sometimes called a dictator, but this is about as accurate as calling him an asshole. It’s just an insult, not a statement of reality. He has no small measure of political skill, but he’s also been blessed with an incompetent opposition. While the opposition’s leadership has proved immovable, the party members have budged quite willingly, effectively enable Mahinda to take a two-thirds majority when he needed it, and to poach MPs almost at will.
Because both the UNP and JVP have become almost feudal preserves of non-charismatic leaders, they more than anyone have destroyed the opposition in Sri Lanka.