The angry tweets started about three hours ago when Marcus asked his brother if he was going to a party.
"@LiamWilliams1 Wer r you... P.s It's our Daniels 18th tomorrow"
To which Liam replied: "@MarcuscollinsUK bak 4 his 18th? he havin a party? i'v already got plans @africaoye didnt know about it, i wont be ready for a couple hours"
Marcus tweeted: "@LiamWilliams1 he's not having a party! If I'm bk Il go @africaoye and what's new #disappointment"
"@MarcuscollinsUK gta wait 4 garage 2 ring 4 beetle n planned haircuts wit @MarkJRudd ages ago 4 b4 @africaoye #Soz4HavinStuff2Do #IHaveALife" Liam said.
"@LiamWilliams1 u don't have a life u barely have mates! U have shit cars that's about it! #Arsehole," Marcus angrily tweeted back.
Liam replied: "@MarcuscollinsUK hope u do well in life n av longevity in ur career son, cz i dont av it in me 2 laff when u fail and i succeed #conceited?"
Judging by Liam's next tweet Marcus blocked his brother, leading him to link to a website which said Marcus' second single Mercy had only got to Number 663 on the iTunes chart.
@clairelsutton @MarcuscollinsUK i'm blocked. #curseorblessing? really not arsed anymore good luck to him... #narcissist"
Marcus wasn't going to let Liam get away with that.
@LiamWilliams1 haha made up with ur tweets shall we start airing some Dirty laundry shall we? Hmm where to start! U really want to play this"
Marcus then added: @LiamWilliams1 hardly narcissistic more of a realist which is why u better come outside
"Usually when people tell lies about me I feel hurt but on this occasion I'm made up! Coz I'm gonna make sure the truth is comin out!"
Liam's most recent tweets said: "find it amusing that marcus seems to think i've lied about something :S putting stories in the press about my fam? exposing the truth? #eh?
"truth about what exactly? i havent lied, got abusive txts off him thats all... y would ppl care about my family? #i'mnotfamous
So what's going on with Marcus and his brother? We've got a feeling this isn't just to do with Daniel's 18th...