That quote is the important bit. It's not strictly true, as arguably there is still non-electronic wealth in the country - but it is massively disproportional to bank created electronic wealth (32:1). Banks create money through measures such as giving out loans - ergo by creating a debt with the loan taker. In theory, the loan taker spends the money which is distributed amongst various people, and is eventually paid back to the bank. The system is however deliberately flawed:
1) It means that for every £33 you have in your UK bank account, someone owes £32. This isn't a problem if your society has decent wage equality, but we don't by a long shot. Consider as an example the average Premiere League Football salary is around £1.25 million per year and there are around 600 players in that league - those football players accumulate more money than they can possibly spend (£750 million per year between them), which means somewhere there has to be a debt of £730 million created to sustain wealth that is just festering in accounts. Footballers are just one example where numbers are easily obtained thanks to transparency. There are of course numerous corporate execs earning far more, many of whom have dangerous ties to our political system.
2) This is all of course assuming that all of your electronic money gets spent in your own country; it naturally doesn't thanks to international trade. Colossal sums of money are taken out of the country by multinational corporations, often abusing loopholes in the tax system so that not even that 20% corporation tax comes back (sometimes, less than 1% comes back). Now we have billions festering in offshore accounts instead.
3) Banks charge interest on everything. They charge interest on loans, they charge fees for holding accounts, fees for transactions, anything they can monetise. This is the most obvious flaw; if wealth is created when a loan is given by the bank and destroyed when a debt is paid - consider what is happening when the amount to be repaid is always more than what is given? The result is that more and more physical wealth is destroyed, and that's how we've reached that 1:32 ratio. People will tell you they own a house - but in reality that house is just another expensive debt to the bank (with interest) in the form of a mortgage. If everyone simultaneously either paid off their mortgages or defaulted and their property was to be possessed by the bank, it is reasonable to consider that banks could own 32 in every 33 properties in the country. That's scary.
Now finally, here's a delightful consideration - if after all this, the people oew the banks, the government owe the banks, but the banks still owe enough debt to have to be bailed out, who the fuck do they actually owe the debt to?