Borussia Dortmund manager Jurgen Klopp has criticised the Premier League for spending "insane" amounts of money in the summer transfer window. The German, who lead the club to the 2011 and 2012 Bundesliga titles and the 2013 Champions League final, singled out two transfers in particular - Mesut Ozil's move from Real Madrid to Arsenal and Gareth Bale's switch from Tottenham to the Santiago Bernabeu.

Mesut Ozil [Real Madrid to Arsenal FC]

"It's insane what happens in England. 80% of the players, for whom the clubs spent €700m (£600m), I don't even know. It doesn't matter how much a player costs. The question is if you really want him and finally if you can pay. The amounts are crazy," Klopp explained to German publication Bild.

"The transfer of Ozil is incredible. That doesn't happen often, €50m (£42.5m) on the last day," he added.

According to business advisory firm Deloitte, the Premier League spent £630m this summer, which is 29% more than the sum spent in 2012 and more than 25% higher than the previous record of £500m, set in 2008.

"The story of this summer transfer window is of new records: a new record for Premier League spending as well as a new world transfer record fee. Whilst the sale of Gareth Bale brought £85m into the Premier League, net spending is also a record, at £400m," Dan Jones of Deloitte explained.

"As the financial rewards for participation and success in the Premier League increase, so it follows that clubs are investing on the pitch to ensure they continue to benefit from the remarkable Premier League growth story," he continued.

Improved Revenues Drive PL Spending

A major reason why top flight English clubs have spent so much this season is the massive television broadcast deal. BT Sport will pay out £738m over three years and Sky a jaw-dropping £2.3bn for 116 matches a season, meaning the Premier League will pocket £3bn over the next 36 months.

"This is the first year that Premier League clubs will benefit financially from the league's new broadcast deals; each club benefitting from a share of the extra £600m of revenues in 2013-14 alone," Alex Thorpe, a Deloitte consultant explained. The calculations are, in fact, truly staggering. According to the Guardian, this means the club that finishes 20th and last in the 2013/14 Premier League season could receive more than the £60.6m Manchester City earned as champions in 2012.

Arsenal v Everton

And given such enormous revenue streams are to continue for at least two more seasons, it is very likely the Premier League will once again flex its considerable financial muscles next summer (or maybe even in the winter transfer window), leaving La Liga, Serie A and the Bundesliga some considerable distance behind.

Bundesliga Spending

Meanwhile, it should be noted the 46-year-old Stuttgart native was not shy about splashing the cash himself though, with Armenia international Henrikh Mkhitaryan joining from Ukrainian champions Shakhtar Donetsk for £23.1m and Gabonese forward Pierre-Emerick Aubameyang coming onboard from Ligue 1 club AS Saint-Etienne for £11m.

All in all, Dortmund are believed to have spent close to £43m themselves and champions Bayern Munich topped even that with £53m in new players. Vfl Wolfsburg, Schalke 04 and Bayer Leverkusen spent over £17m each.

Interestingly though, the spread of transfer expenditure is much narrower in the Bundesliga than the Premier League, with the German top flight doing only £230m worth of business, according to Deloitte. The Spanish and Italian leagues fell in between the two, with over £300m each.