The Parliament of the 1640s was very different to the one we know now. No Prime Minister's Question Time, highly organised parties, or leaders of the opposition. All MPs and Lords were assumed to be loyal to the Crown. There was no concept of an 'official' or 'loyal' opposition. Yet there were parties and groups within the Commons. And in the 1640 Parliament, there was a clear split between a Court party, many of whom were ministers in Charles' administration, and an unofficial, opposition group who were inspired by religious and constitutional hostility to the King.
After eleven years of personal rule and no representation, Parliament was back. Throughout the 1630s, Charles had governed without calling a Parliament. Some condemned it as tyranny but it was not a totally abnormal procedure. Parliaments were only called when monarchs needed revenue from taxes or wider support for war or social and religious reforms. Elizabeth went for years without summoning a Parliament, while James VI/I governed without Parliament for seven years.
Charles' situation in 1640 was fraught because during the eleven years of personal rule, he had operated without a proper income from tax revenue.
Parliament was required to sanction a proper taxation revenue, so for eleven years, Charles kept himself and his administration afloat through a variety of levies which Parliament hadn't sanctioned. The most notorious was Ship Money - a tax for the navy which Charles extended from coastal counties to the whole country and then siphoned off for his own use. There were other revenue raising schemes, such as fines on encroaching royal forests or the sale of monopoly licences, all of which served to alienate the wealthy, political classes (the King's natural allies) many of whom were MPs. And they'd had eleven years to build up their anger.
When Parliament met in April 1640, Charles hoped for a show of loyalty from his English subjects. However, the bruises of the 1630s were there for all to see. Petitions flooded in complaining about Ship Money and Laudian church policy. The Commons held out the prospect of twelve subsidies for Charles but linked them to a long list of grievances. Before they gave any money, they wanted some reforms to church policy and taxation.
The Court party in Parliament abjectly failed to govern the direction of debate. And when it began to emerge that some Parliamentarians sympathetic to Presbyterianism were, in fact, in contact with the Scottish Covenanters, and were supportive of their struggle, the very purpose of calling a Parliament (to help beat the Scots) now seemed futile. Few Parliamentarians could see precisely what the Covenanters had done wrong. They were more worried by Laud's religious innovations in England than any Presbyterianism in Scotland. The King was now being conspired against by some within Parliament who were working hand in glove with the Covenanter rebels. After three weeks of tumultuous debate, Charles pulled the plug and dissolved what became known as 'the Short Parliament.'